Input sensing device and display device including the same

ABSTRACT

An input sensing device includes an input sensing panel including driving electrodes and sensing electrodes, a driving signal generator that provides driving signals to the driving electrodes, respectively, and a sensing unit that receives sensing signals according to the driving signals from the sensing electrodes, and determines whether a touch is performed based on the sensing signals. Each of the driving signals includes a sinusoidal wave, and frequencies of at least some of the driving signals are different from each other.

This application is a continuation of U.S. patent application Ser. No.17/217,204, filed on Mar. 30, 2021, which claims priority to KoreanPatent Application No. 10-2020-0104909 filed on Aug. 20, 2020, and allthe benefits accruing therefrom under 35 U.S.C. § 119, the content ofwhich in its entirety is herein incorporated by reference.

BACKGROUND 1. Field

Embodiments of the invention relate to an input sensing device and adisplay device including the same.

2. Description of the Related Art

A display device may include a display panel displaying an image, and atouch panel disposed on the display panel to receive a touch input.

The touch panel includes a plurality of sensing electrodes, and senses achange in capacitance generated on the plurality of sensing electrodesto find a touched point.

SUMMARY

Since a display driving signal driving a display panel acts as noise ona touch panel, a touch driving signal driving the touch panel is set toavoid the display driving signal (for example, a horizontalsynchronization signal).

However, as a display device is driven at high speed, a frequency of thedisplay driving signal increases (for example, the frequency increasesfrom 60 Hertz (Hz) to 120 Hz, etc., in other words, a period of thedisplay driving signal decreases). Therefore, a period of the touchdriving signal may decrease, and then a time for touch sensing maydecrease.

In addition, as the display device becomes thinner and larger, a gapbetween the display panel and the touch panel (or touch electrodes)decreases, an overlapping area between the display panel and the touchpanel increases. Therefore, parasitic capacitance increases so thattouch sensing sensitivity may decrease.

An embodiment of the invention provides an input sensing device havingimproved touch sensing sensitivity even in an environment (for example,a high-speed driving, thinning, and large-sized display device) in whicha performance of a touch sensor is degraded, and a display deviceincluding the same.

An input sensing device in an embodiment of the invention includes aninput sensing panel including driving electrodes and sensing electrodes,a driving signal generator that provides driving signals to the drivingelectrodes, respectively, a sensing unit that receives sensing signalsaccording to the driving signals from the sensing electrodes, anddetermines whether a touch is performed based on the sensing signals.Each of the driving signals includes a sinusoidal wave, and frequenciesof at least some of the driving signals are different from each other.

In an embodiment, the input sensing panel may include a first area and asecond area, and the first area may be farther from the driving signalgenerator or the sensing unit than the second area is from the drivingsignal generator or the sensing unit, and a first frequency of a firstdriving signal provided to the first area among the driving signals maybe smaller than a second frequency of a second driving signal providedto the second area among the driving signals.

In an embodiment, the driving electrodes may include a first drivingelectrode farthest from the sensing unit in the first area, and a seconddriving electrode closest to the sensing unit in the second area, andthe first driving signal may be applied to the first driving electrode,and the second driving signal may be applied to the second drivingelectrode.

In an embodiment, a level of the sensing signals when the second drivingsignal is applied to the first driving electrode may be smaller than orequal to half the level of the sensing signals when the second drivingsignal is applied to the second driving electrode.

In an embodiment, the driving electrodes may include first drivingelectrodes provided in the first area and second driving electrodesprovided in the second area, and the driving signal generator mayprovide the first driving signal to each of the first drivingelectrodes, and may provide the second driving signal to each of thesecond driving electrodes.

In an embodiment, the driving signal generator may sequentially providethe driving signals to the driving electrodes.

In an embodiment, the driving signal generator may simultaneouslyprovide the driving signals to the driving electrodes.

In an embodiment, the driving signal generator may include a waveformgenerator that generates a reference signal including a sinusoidal wave,and a frequency modulator that varies a frequency of the referencesignal through frequency division and generates the driving signals.

In an embodiment, the sensing unit may sample a first sensing signalaccording to the first driving signal N times during a reference time,and may sample a second sensing signal according to the second drivingsignal N times during the reference time where N is an integer greaterthan four.

In an embodiment, a first sensing value generated by sampling the firstsensing signal during the reference time is greater than a secondsensing value generated by sampling the second sensing signal during thereference time, and attenuation of the first driving signal and thefirst sensing signal may be compensated by a difference between thefirst sensing value and the second sensing value.

In an embodiment, the reference time may be smaller than or equal to afirst period of the first driving signal.

In an embodiment, the reference time may be smaller than half of thefirst period of the first driving signal, and each of the sensingsignals according to the first driving signal may have a maximum valueduring the reference time.

In an embodiment, amplitudes of the driving signals may be differentfrom each other.

In an embodiment, an amplitude of at least one of the driving signals isvariable, and each of the driving signals may have a maximum amplitudeduring the reference time.

In an embodiment, the sensing unit may include analog front-ends thatreceives sensing signals according to the driving signals from thesensing electrodes, and a signal processing unit that determines whethera touch is performed based on differential output values of the analogfront-ends.

In an embodiment, each of the analog front-ends may include a chargeamplifier that differentially amplifies a first sensing signal and asecond sensing signal respectively provided from two sensing electrodesadjacent to each other among the sensing electrodes and outputs a firstdifferential signal and a second differential signal complementary toeach other, a band pass filter that filters the first differentialsignal and the second differential signal and outputs a first filteredsignal and a second filtered signal, respectively, a mixer that changesfrequencies of the first filtered signal and the second filtered signaland outputs a first demodulated signal and a second demodulated signal,respectively, a low pass filter that filters noise from the firstdemodulated signal and the second demodulated signal and outputs a firstoutput signal and a second output signal, respectively, and ananalog-to-digital converter that outputs a differential output valuecorresponding to a difference between the first output signal and thesecond output signal.

In an embodiment, the input sensing device may further include adistribution circuit that is disposed between at least some of thesensing electrodes and the analog front-ends, and provides each of thesensing signals provided from at least some of the sensing electrodes totwo adjacent analog front-ends of the analog front-ends.

In an embodiment, the input sensing device may further include anegative capacitor connected to a front-end of each of the analogfront-ends.

In an embodiment, each of the analog front-ends may include amultiplexer that selects two sensing signals from sensing signalsprovided from three adjacent sensing electrodes among the sensingelectrodes, a charge amplifier that differentially amplifies the twosensing signals selected from the sensing signals and outputs a firstdifferential signal and a second differential signal complementary toeach other, a band pass filter that filters the first differentialsignal and the second differential signal and outputs a first filteredsignal and a second filtered signal, respectively, a mixer that changesfrequencies of the first filtered signal and the second filtered signaland outputs a first demodulated signal and a second demodulated signal,respectively, a low pass filter that filters noise from the firstdemodulated signal and the second demodulated signal and outputs a firstoutput signal and a second output signal, respectively, and ananalog-to-digital converter that outputs a differential output valuecorresponding to a difference between the first output signal and thesecond output signal.

In an embodiment, the multiplexer may select a first sensing signal anda second sensing signal from the sensing signals in a first section, mayselect a second sensing signal and a third sensing signal from thesensing signals in a second section different from the first section,and the first to third sensing signals may be respectively provided fromthe three sensing electrodes.

A display device in an embodiment of the invention includes a displaypanel including pixels that emit light in unit of frame, an inputsensing panel that includes driving electrodes and sensing electrodes, adriving signal generator that provides driving signals to the drivingelectrodes, respectively, and a sensing unit that receives sensingsignals according to the driving signals from the sensing electrodes,and determines whether a touch is performed based on the sensingsignals. Each of the driving signals includes a sinusoidal wave, andfrequencies of at least some of the driving signals are different fromeach other.

In an embodiment, the driving signal generator provides the drivingsignals to the driving electrodes by avoiding a section in which a pulseof a vertical synchronization signal defining a start of the frame isgenerated.

In an embodiment, the driving signal generator may block a supply of thedriving signals in the section in which the pulse of the verticalsynchronization signal is generated.

In an embodiment, the driving signals may be asynchronous with ahorizontal synchronization signal, and the horizontal synchronizationsignal may define a section in which a line image is output throughpixels included in a same line among the pixels.

A sensing device in an embodiment of the invention includes a sensingpanel including first electrodes and second electrodes, a driver thatprovides driving signals to the first electrodes, respectively, and asensing unit that receives sensing signals according to the drivingsignals from the second electrodes. Each of the driving signals mayinclude a sinusoidal wave, at least one of the driving signals may havea first frequency, at least another one of the driving signals may havea second frequency, and the first frequency and the second frequency maybe different from each other.

An input sensing device and a display device in embodiments of theinvention may generate touch driving signals including a sinusoidalwave, so that a frequency of the touch driving signal may be freely setregardless of a frequency of a horizontal synchronization signal, and adecrease in a bandwidth of the touch driving signal may be prevented.Accordingly, a decrease in sensing sensitivity due to the decrease inthe bandwidth of the touch driving signal may be prevented.

In addition, the input sensing device and the display device inembodiments of the invention may generate touch driving signals havingdifferent frequencies, and may provide a touch driving signal having arelatively small frequency to a driving electrode with a relativelylarge resistance-capacitance (“RC”) delay (or, response delay).Accordingly, a decrease in sensing sensitivity due to RC delay may beprevented.

Further, the input sensing device and the display device in embodimentsof the invention may generate sensing values by sampling sensing signalscorresponding to touch driving signals having different frequencies at asame number of sampling times, so that signal attenuation of a sensingsignal (i.e., sensing signal having a relatively large RC delay)corresponding to a touch driving signal having a relatively smallfrequency may be compensated. Accordingly, the touch sensing sensitivitymay be uniform throughout the sensing area.

Effects of embodiments of the invention is not limited by what isillustrated in the above, and more various effects are included in thespecification.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other embodiments, advantages and features of thisdisclosure will become more apparent by describing in further detailembodiments thereof with reference to the accompanying drawings, inwhich:

FIG. 1 is a drawing illustrating an embodiment of an input sensingdevice.

FIG. 2A is a drawing illustrating an equivalent circuit for a circuitconfiguration between a driving signal generator and a sensing unitincluded in the input sensing device of FIG. 1 .

FIG. 2B is a drawing illustrating an embodiment of a touch drivingsignal and a sensing signal.

FIG. 2C is a drawing illustrating intensity of a sensing signal based onan input location of a touch driving signal.

FIG. 3A is a drawing illustrating intensity of a sensing signal based ona frequency of a touch driving signal.

FIG. 3B is a drawing illustrating an embodiment of a touch drivingsignal generated by a driving signal generator included in the inputsensing device of FIG. 1 .

FIGS. 3C and 3D are drawings illustrating another embodiment of a touchdriving signal generated by a driving signal generator included in theinput sensing device of FIG. 1 .

FIGS. 4A to 4C are drawings illustrating embodiments of touch drivingsignals generated by a driving signal generator included in the inputsensing device of FIG. 1 .

FIG. 5 is a block diagram illustrating an embodiment of a driving signalgenerator included in the input sensing device of FIG. 1 .

FIGS. 6A and 6B are block diagrams illustrating an embodiment of ananalog front end included in the input sensing device of FIG. 1 .

FIG. 7A is a circuit diagram illustrating an embodiment of a chargeamplifier included in the analog front end of FIG. 6A.

FIG. 7B is a drawing illustrating an embodiment of signals forexplaining an operation of the analog front end of FIG. 6A.

FIG. 8 is a drawing illustrating a sampling operation of ananalog-to-digital converter included in the analog front end of FIG. 6A.

FIGS. 9A and 9B are drawings illustrating an embodiment of sensingvalues based on the number of sampling times of an analog-to-digitalconverter included in the analog front end of FIG. 6A.

FIG. 10 is a drawing illustrating another embodiment of an operation ofan analog-to-digital converter included in the analog front end of FIG.6A.

FIG. 11 is a drawing illustrating another embodiment of an input sensingdevice.

FIG. 12 is a diagram illustrating another embodiment of an input sensingdevice.

FIG. 13 is a block diagram illustrating an embodiment of an analog frontend included in the input sensing device of FIG. 12 .

FIG. 14 is a drawing illustrating an input sensing device.

FIG. 15 is a block diagram illustrating an embodiment of an analog frontend included in the input sensing device of FIG. 14 .

FIG. 16 is a drawing illustrating an operation of a multiplexer includedin the analog front end of FIG. 15 .

FIG. 17A is a block diagram illustrating another embodiment of an analogfront end included in the input sensing circuit of FIG. 14 .

FIG. 17B is a block diagram illustrating another embodiment of an analogfront end included in the input sensing circuit of FIG. 1 .

FIG. 18 is a perspective view illustrating an embodiment of a displaydevice.

FIG. 19 is a plan view illustrating an embodiment of a display panelincluded in the display device of FIG. 18 .

FIG. 20 is a plan view illustrating an embodiment of an input sensingpanel included in the display device of FIG. 18 .

FIG. 21 is an enlarged plan view of a partial area FF of the inputsensing panel of FIG. 20 .

FIG. 22 is a cross-sectional view illustrating an embodiment of adisplay device taken along line I-I′ of FIG. 21 .

DETAILED DESCRIPTION

Hereinafter, with reference to accompanying drawings, variousembodiments of the invention will be described in detail so that thoseskilled in the art may easily carry out the invention. Embodiments ofthe invention may be embodied in many different forms and is not limitedto the embodiments described herein.

In order to clearly illustrate the invention, parts that are not relatedto the description are omitted, and the same or similar constituentelements are given the same reference numerals throughout thespecification. Therefore, the above-mentioned reference numerals can beused in other drawings.

It will be understood that when an element is referred to as being “on”another element, it can be directly on the other element or interveningelements may be present therebetween. In contrast, when an element isreferred to as being “directly on” another element, there are nointervening elements present.

It will be understood that, although the terms “first,” “second,”“third” etc. may be used herein to describe various elements,components, regions, layers and/or sections, these elements, components,regions, layers and/or sections should not be limited by these terms.These terms are only used to distinguish one element, component, region,layer or section from another element, component, region, layer orsection. Thus, “a first element,” “component,” “region,” “layer” or“section” discussed below could be termed a second element, component,region, layer or section without departing from the teachings herein.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms, including “at least one,” unless the content clearly indicatesotherwise. “Or” means “and/or.” As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items. It will be further understood that the terms “comprises”and/or “comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

Furthermore, relative terms, such as “lower” or “bottom” and “upper” or“top,” may be used herein to describe one element's relationship toanother element as illustrated in the Figures. It will be understoodthat relative terms are intended to encompass different orientations ofthe device in addition to the orientation depicted in the Figures. Forexample, if the device in one of the figures is turned over, elementsdescribed as being on the “lower” side of other elements would then beoriented on “upper” sides of the other elements. The exemplary term“lower,” can therefore, encompasses both an orientation of “lower” and“upper,” depending on the particular orientation of the figure.Similarly, if the device in one of the figures is turned over, elementsdescribed as “below” or “beneath” other elements would then be oriented“above” the other elements. The exemplary terms “below” or “beneath”can, therefore, encompass both an orientation of above and below.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” can mean within one or morestandard deviations, or within ±30%, 20%, 10%, 5% of the stated value.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein. A term such as“unit” may mean a circuit or a processor.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, a region illustrated or described asflat may, typically, have rough and/or nonlinear features. Moreover,sharp angles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the present claims.

In addition, since the size of each configuration shown in the drawingare arbitrarily shown for better understanding and ease of description,the invention is not necessarily limited to the illustrated one.

FIG. 1 is a drawing illustrating an embodiment of an input sensingdevice.

Referring to FIG. 1 , an input sensing device ISU may include an inputsensing panel ISP and an input sensing circuit IS-C.

The input sensing panel ISP may include a sensing area SA that senses aninput of a user, for example, a touch and/or a pressure when touching,and a peripheral area PA provided on at least one side of the sensingarea SA.

The input sensing panel ISP may include driving electrodes IE1-1 toIE1-5 (or first sensing electrodes, transmission electrodes) and sensingelectrodes IE2-1 to IE2-4 (or second sensing electrodes, receivingelectrodes) provided in the sensing area SA, and driving signal linesSL1-1 to SL1-5 (or first signal lines, transmission signal lines) andsensing signal lines SL2-1 to SL2-4 (or second signal lines, receivingsignal lines) provided to the peripheral area PA.

The driving electrodes IE1-1 to IE1-5 may extend in a second directionDR2, and may be spaced apart from one another in a first direction DR1.The sensing electrodes IE2-1 to IE2-4 may extend in the first directionDR1, and may be spaced apart from one another in the second directionDR2. A more specific configuration of the driving electrodes IE1-1 toIE1-5 and the sensing electrodes IE2-1 to IE2-4 will be described laterwith reference to FIG. 20 .

In an embodiment, the sensing area SA may include a first area A1 and asecond area A2 separated from each other. The first area A1 may bespaced apart from an input sensing circuit IS-C disposed at one side ofthe sensing area SA, and the second area A2 may be adjacent to the inputsensing circuit IS-C. The second area A2 may be disposed between theinput sensing circuit IS-C and the first area A1. That is, the firstarea A1 and the second area A2 may be divided based on a distance spacedapart from the input sensing circuit IS-C (or length of a signalmovement path of the touch driving signal and the sensing signal, orresistance-capacitance (“RC”) delay).

In an embodiment, the first area A1 may include a first drivingelectrode IE1-1 that is farthest from the input sensing circuit IS-C anda second driving electrode IE1-2 that is second farthest from the inputsensing circuit IS-C, for example. In an embodiment, the second area A2may include a third driving electrode IE1-3, a fourth driving electrodeIE1-4, and a fifth driving electrode IE1-5 closest to the input sensingcircuit IS-C, for example.

In FIG. 1 , the sensing area SA is illustrated as including two areas A1and A2, but is not limited thereto. In an embodiment, the sensing areaSA may include three or more areas, and as an area of the input sensingpanel ISP (and the sensing area SA) becomes larger, the sensing area SAmay also be divided into a larger number of areas, for example.

The driving signal lines SL1-1 to SL1-5 may be connected to one end ofthe driving electrodes IE1-1 to IE1-5, respectively. In an embodiment,the first driving signal line SL1-1 may be connected to the firstdriving electrode IE1-1, and the fifth driving signal line SL1-5 may beconnected to the fifth driving electrode IE1-5, for example. The firstdriving signal line SL1-1 may be longer than the fifth driving signalline SL1-5, and may be also longer than the second driving signal lineSL1-2, the third driving signal line SL1-3, and the fourth drivingsignal line SL1-4. Also, a resistance value of the first driving signalline SL1-1 may be greater than a resistance value of the fifth drivingsignal line SL1-5.

The sensing signal lines SL2-1 to SL2-4 may be connected to one end ofthe sensing electrodes IE2-1 to IE2-4. In an embodiment, the firstsensing signal line SL2-1 may be connected to the first sensingelectrode IE2-1, and the fourth sensing signal line SL2-4 may beconnected to the fourth sensing electrode IE2-4. Lengths of the sensingsignal lines SL2-1 to SL2-4 may be the same, for example, but are notlimited thereto.

In embodiments, the sensing signal lines SL2-1 to SL2-4 may be connectedto both ends of the sensing electrodes IE2-1 to IE2-4, which will bedescribed later with reference to FIG. 20 .

In FIG. 1 , the input sensing panel ISP is shown to include five drivingelectrodes IE1-1 to IE1-5 and four sensing electrodes IE2-1 to IE2-4,but the number of the driving electrodes IE1-1 to IE1-5 and the numberof the sensing electrodes IE2-1 to IE2-4 are not limited thereto. In anembodiment, the input sensing device ISU may include six or more drivingelectrodes and/or five or more sensing electrodes, for example.

The input sensing circuit IS-C may include a driving signal generatorTXD (or driver) and a sensing unit RXD.

The driving signal generator TXD may generate touch driving signals TX1to TX5 (or driving signals), and may provide the touch driving signalsTX1 to TX5 to the driving electrodes IE1-1 to IE1-5, respectively. In anembodiment, the driving signal generator TXD may provide the first touchdriving signal TX1 to the first driving electrode IE1-1, may provide thesecond touch driving signal TX2 to the second driving electrode IE1-2,may provide the third touch driving signal TX3 to the third drivingelectrode IE1-3, may provide the fourth touch driving signal TX4 to thefourth driving electrode IE1-4, and may provide the fifth touch drivingsignal TX5 to the fifth driving electrode IE1-5, for example.

Each of the touch driving signals TX1 to TX5 may include a sinusoidalwave such as a sine wave or a cosine wave. A level change of thesinusoidal wave over time appears in the form of a sine curve or acosine curve, and appears more gently than that of a square wave. Wheneach of the touch driving signals TX1 to TX5 has a square wave, thelevel change is fast. Therefore, it may be easy to increase thefrequency of the touch driving signals TX1 to TX5, but the sensingsignals based on the touch driving signals TX1 to TX5 have a differentwaveform from the touch driving signals TX1 to TX5 due to an RC delay,so it may not be easy to remove noise from the sensing signal. In anembodiment, the sensing signal may be compared with the correspondingtouch driving signal, and then a portion where the level change of thesensing signal differs from the level change of the touch driving signalmay be extracted and removed as noise, for example. When the touchdriving signal is a square wave, due to the RC delay (e.g., charging anddischarging of the capacitance), a tangential slope of the level of thesensing signal may be gently changed or distorted below a predeterminedvalue (i.e., the waveform of the sensing signal may be different fromthe waveform of the touch driving signal). Even due to noise, the levelchange of the sensing signal may appear different from the level changeof the touch driving signal, and it may not be easy to distinguishwhether the level change of the sensing signal is due to only the RCdelay or both the RC delay and the noise. When each of the touch drivingsignals TX1 to TX5 includes a sinusoidal wave, the sensing signals basedon the touch driving signals may have the same wave as or a similarsinusoidal wave to those of the touch driving signals, even when the RCdelay occurs, so that the noise may be easily removed from the sensingsignals. Even when the RC delay occurs, since the level change of thetouch driving signal of the sinusoidal wave is gentle, only a phase ofthe sensing signal is different from a phase of the touch drivingsignal, and the waveform of the sensing signal may be the same as thatof the touch driving signal. Accordingly, a portion where the levelchange of the sensing signal differs from the level change of the touchdriving signal may be determined to be due to noise without consideringthe RC delay, and thus the noise may be easily removed.

In an embodiment, at least some of the touch driving signals TX1 to TX5may have different frequencies FREQ1 to FREQ5 (or driving periods) fromone another. In an embodiment, the first touch driving signal TX1 mayhave the first frequency FREQ1, and the fifth touch driving signal TX5may have the fifth frequency FREQ5, for example. The fifth frequencyFREQ5 may be greater than the first frequency FREQ1. The secondfrequency FREQ2 of the second touch driving signal TX2 and the thirdfrequency FREQ3 of the third touch driving signal TX3 may be the same asthe first frequency FREQ1 of the first touch driving signal TX1. Thefourth frequency FREQ4 of the fourth touch driving signal TX4 may be thesame as the fifth frequency FREQ5 of the fifth touch driving signal TX5.That is, the frequency of the touch driving signal applied to the secondarea A2 closer to the input sensing circuit IS-C may be greater than thefrequency of the touch driving signal applied to the first area A1farther from the input sensing circuit IS-C. As another example, thefrequencies FREQ1 to FREQ5 of the touch driving signals TX1 to TX5 maybe all different from one another.

As will be described later with reference to FIGS. 2A, 2B, and 3A, sincethe first driving electrode IE1-1 is farther from the input sensingcircuit IS-C than the fifth driving electrode IE1-5 is from the inputsensing circuit IS-C, the RC delay of the first touch driving signal TX1(and sensing signal corresponding thereto) may be greater than the RCdelay of the fifth touch driving signal TX5 (and sensing signalcorresponding thereto). Accordingly, when a touch driving signal havinga high-frequency is applied to the first driving electrode IE1-1, thesensing signal cannot follow the touch driving signal due to arelatively large RC delay, and thus the sensitivity of the sensingsignal may decrease. Accordingly, the first touch driving signal TX1 mayhave a relatively low frequency. The fifth touch driving signal TX5 mayalso have a low frequency, but in this case, since the sensing time ofthe input sensing device ISU may increase, it may not be suitable fordriving the large-area input sensing panel ISP. Accordingly, in order toshorten the sensing time of the input sensing device ISU, the fifthtouch driving signal TX5 may have a relatively high frequency.

In an embodiment, the driving signal generator TXD may provide the touchdriving signals TX1 to TX5 to the driving electrodes IE1-1 to IE1-5sequentially (i.e., sequentially driving) or simultaneously (i.e.,simultaneously driving or parallelly driving). A configuration in whichthe driving signal generator TXD provides the touch driving signals TX1to TX5 to the driving electrodes IE1-1 to IE1-5 will be described laterwith reference to FIGS. 4A, 4B, and 4C.

According to the touch driving signals TX1 to TX5 provided to thedriving electrodes IE1-1 to IE1-5, a sensing capacitance may be disposedbetween the driving electrodes IE1-1 to IE1-5 and the sensing electrodesIE2-1 to IE2-4. In an embodiment, the 1-1-th sensing capacitance C11 maybe generated between the first driving electrode IE1-1 and the firstsensing electrode IE2-1, for example. In an embodiment, the 5-1-thsensing capacitance C51 may be generated between the fifth drivingelectrode IE1-5 and the first sensing electrode IE2-1, for example.

The sensing unit RXD may receive sensing signals based on the touchdriving signals TX1 to TX5 from the sensing electrodes IE2-1 to IE2-4,and may determine whether a touch has been performed based on thesensing signals.

The sensing unit RXD may include analog front-ends AFE1 to AFE4, and asignal processing unit DSP.

Each of the analog front-ends AFE1 to AFE4 may be connected to twoadjacent sensing electrodes (or second signal lines) among the sensingelectrodes IE2-1 to IE2-4, and may output a sensing value (or adifferential output value) corresponding to a difference in sensingcapacitances. In an embodiment, the first analog front-end AFE1 may beconnected to the first sensing electrode IE2-1 and the second sensingelectrode IE2-2, and may output a first sensing value corresponding to adifference between a sensing capacitance generated on the first sensingelectrode IE2-1 and a sensing capacitance generated on the secondsensing electrode IE2-2, for example. Similarly, the second analogfront-end AFE2 may be connected to the second sensing electrode IE2-2and the third sensing electrode IE2-3, and may output a second sensingvalue corresponding to a difference between a sensing capacitancesgenerated on the second sensing electrode IE2-2 and a sensingcapacitance generated on the third sensing electrode IE2-3.

When a touch event occurs in a predetermined region of the input sensingpanel ISP, a sensing capacitance between a driving electrode and asensing electrode disposed in the corresponding region may be changed.In an embodiment, when a touch event occurs in a region where the firstdriving electrode IE1-1 and the first sensing electrode IE2-1 intersect,a size of the 1-1-th sensing capacitance between the first drivingelectrode IE1-1 and the first sensing electrode IE2-1 may be changed,for example. A size of the 1-2-th sensing capacitance between the firstdriving electrode IE1-1 and the second sensing electrode IE2-2 adjacentto the first sensing electrode IE2-1 may not be changed. Accordingly,the first sensing value output through the first analog front-end AFE1may be changed, and a location where a touch occurs may be detectedbased on the changed first sensing value.

Each of the analog front-ends AFE1 to AFE4 may include an amplifier, afilter, an analog-to-digital converter, and the like, and apredetermined configuration of each of the analog front-ends AFE1 toAFE4 will be described later with reference to FIG. 6A.

In an embodiment, each of the analog front-ends AFE1 to AFE4 may beimplemented as a fully differential analog front-end. In an embodiment,when the first analog front-end AFE1 includes a charge amplifier, achopping circuit, filters, and an analog-to-digital convertersequentially connected, the first analog front-end AFE1 maydifferentially amplify the first sensing signal corresponding to thesensing capacitance of the first sensing electrode IE2-1 and the secondsensing signal corresponding to the sensing capacitance of the secondsensing electrode IE2-2 by the charge amplifier to output twodifferential signals, may demodulate each of the two differentialsignals by the chopping circuit and the filters, may filter each of thetwo demodulated differential signals, and may provide the filtered twodifferential signals to the analog-to-digital converter, for example. Inthis case, the analog-to-digital converter may output the first sensingvalue based on the difference between the filtered two differentialsignals. That is, the fully differential analog front-end may be ananalog front-end that converts analog sensing signals provided from thesensing electrodes into a plurality of differential signals, maintains,and outputs to a front end of the analog-to-digital converter (i.e.,until converting an analog signal into a digital signal). For reference,the charge amplifier and the filters may include amplifiers, a voltagerange of the charge amplifiers and the filters in a low voltage systemis limited, and a general analog front-end may not utilize all thedynamic range of an analog-to-digital converter. Accordingly, the fullydifferential analog front-end may provide two differential signals tothe analog-to-digital converter, thereby doubling the dynamic range ofthe analog-to-digital converter or a range of utilization of the dynamicrange, and improving touch sensing sensitivity.

The sensing values output from the analog front-ends AFE1 to AFE4 may beprovided to the signal processing unit DSP, and the signal processingunit DSP may determine whether a touch is performed or calculate aposition where the touch is performed based on the sensing values.

As described with reference to FIG. 1 , the input sensing device ISU maygenerate the touch driving signals TX1 to TX5 including sinusoidal waveshaving different frequencies respectively, may provide a touch drivingsignal having a relatively small frequency (e.g., first touch drivingsignal TX1 having a first frequency FREQ1) to driving electrodes (e.g.,first driving electrode IE1-1 in the first area A1) having a relativelylarge RC delay. Accordingly, a decrease in sensing sensitivity due tothe RC delay may be prevented.

In addition, the input sensing device ISU may differentially amplifyadjacent sensing signals and remove noise by the fully differentialanalog front-end. Accordingly, the frequency of the touch driving signalmay be set irrespective of a frequency of a signal (e.g., horizontalsynchronization signal) for driving a display device coupled or unitarywith the input sensing device ISU, and a decrease in a bandwidth of thetouch driving signal and a decrease in touch sensing sensitivity duethereto may be prevented.

FIG. 2A is a drawing illustrating an equivalent circuit for a circuitconfiguration between a driving signal generator and a sensing unitincluded in the input sensing device of FIG. 1 . FIG. 2B is a drawingillustrating an embodiment of a touch driving signal and a sensingsignal. FIG. 2C is a drawing illustrating intensity of a sensing signalbased on an input location of a touch driving signal. Hereinafter, forconvenience, an expression such as “resistance X” may mean a resistanceof a resistor X, and an expression such as “capacitance Y” may mean acapacitance of a capacitor Y.

First, referring to FIGS. 1 and 2A, an equivalent circuit shown in FIG.2A may include a transmission resistor R_TX, a transmission capacitorC_TX, a sensing capacitor C_M, a receiving capacitor C_RX, and areceiving resistor R_RX. The transmission resistor R_TX may be connectedbetween the driving signal generator TXD and one electrode of thesensing capacitor C_M, the transmission capacitor C_TX may be connectedbetween the one electrode of the sensing capacitor C_M and the ground,the receiving capacitor C_RX may be connected between the otherelectrode of the sensing capacitor C_M and the ground, and the receivingresistor R_RX may be connected between the other electrode of thesensing capacitor C_M and the sensing unit RXD.

In an embodiment, it is assumed that the equivalent circuit of FIG. 2Arepresents an equivalent circuit for the fifth driving signal lineSL1-5, the fifth driving electrode IE1-5, the 5-1-th sensing capacitanceC51 (i.e., capacitance generated between the fifth driving electrodeIE1-5 and the first sensing electrode IE2-1), the first sensingelectrode IE2-1, and the first sensing signal line SL2-1, for example.

In this case, the transmission resistance R_TX may represent the totalresistance of the fifth driving signal line SL1-5 and the fifth drivingelectrode IE1-5 based on the 5-1-th sensing capacitance C51. Thetransmission capacitor C_TX may represent the total parasiticcapacitance of the fifth driving signal line SL1-5 and the fifth drivingelectrode IE1-5 based on the 5-1-th sensing capacitance C51. The sensingcapacitor C_M may represent the 5-1-th sensing capacitance C51. Thereceiving capacitor C_RX may represent the total parasitic capacitanceof the first sensing electrode IE2-1 and the first sensing signal lineSL2-1 based on the 5-1-th sensing capacitance C51. The receivingresistance R_RX may represent the total resistance of the first sensingsignal line SL2-1 and the first sensing electrode IE2-1 based on the5-1-th sensing capacitance C51.

When the fifth touch driving signal TX5 is applied to the fifth drivingsignal line SL1-5, the fifth touch driving signal TX5 transmitted to thesensing capacitor C_M may have an RC delay due to the transmissionresistor R_TX and the transmission capacitor C_TX. The second sensingsignal provided to the sensing unit RXD in response to the fifth touchdriving signal TX5 and the sensing capacitor C_M may have an RC delaydue to the receiving resistor R_RX and the receiving capacitor C_RX.

Accordingly, as shown in FIG. 2B, the sensing signal RX (e.g., secondsensing signal) in the sensing unit RXD may have an RC delay by apredetermined time DELAY or a predetermined phase based on the touchdriving signal TX (e.g., fifth touch driving signal TX5) provided fromthe driving signal generator TXD. In addition, an amplitude AP_RX of thesensing signal RX may be smaller than an amplitude AP_TX of the touchdriving signal TX due to the transmission resistor R_TX and thereceiving resistor R_RX. That is, attenuation may occur in the sensingsignal RX.

As another example, it is assumed that the equivalent circuit of FIG. 2Arepresents an equivalent circuit for the first driving signal lineSL1-1, the first driving electrode IE1-1, and the 1-1-th sensingcapacitance C11 (i.e., capacitance generated between the first drivingelectrode IE1-1 and the first sensing electrode IE2-1), the firstsensing electrode IE2-1, and the first sensing signal line SL2-1.

In this case, compared with a case for the 5-1-th sensing capacitanceC51, each of the transmission resistance R_TX, the transmissioncapacitor C_TX, the receiving capacitor C_RX, and the receivingresistance R_RX may increase. This is because a length (i.e., paththrough which the first sensing signal corresponding to the first touchdriving signal TX1 moves) of the first driving signal line SL1-1 and thefirst sensing electrode IE2-1 increases, and an area overlapping withother configurations increases. Accordingly, as shown in FIG. 2B,compared with the case for the 5-1-th sensing capacitance C51, an RCdelay of the sensing signal RX (e.g., first sensing signal) in thesensing unit RXD may be greater. In addition, when the RC delayincreases, the sensing capacitor C_M is not sufficiently charged anddischarged, so the amplitude AP_RX of the sensing signal RX may besmaller. Further, since the transmission resistance R_TX and thereceiving resistance R_RX are relatively great, attenuation of thesensing signal RX is relatively great, and the amplitude AP_RX of thesensing signal RX may be smaller.

As shown in FIG. 2C, when the location of the touch driving electrode towhich the touch driving signal TX is applied is closest to the inputsensing circuit IS-C (Near), the intensity of the sensing signal RX maybe the greatest. In an embodiment, when the touch driving signal TX isapplied to the fifth driving electrode IE1-5 in the second area A2, amovement path of the touch driving signal TX and the sensing signal RXcorresponding thereto may be the shortest, for example. Accordingly, inthis case, the RC delay and signal attenuation may be the smallest, thesensing capacitor C_M may be sufficiently charged and discharged, andthe intensity of the sensing signal RX may be the greatest.

As the location of the touch driving electrode to which the touchdriving signal TX is applied is farther from the input sensing circuitIS-C, the intensity of the sensing signal RX may decrease.

When the location of the touch driving electrode to which the touchdriving signal TX is applied is farthest from the input sensing circuitIS-C (Far), the intensity of the sensing signal RX may be the smallest.In an embodiment, when the same touch driving signal TX is applied tothe first driving electrode IE1-1, the movement path of the touchdriving signal TX and the sensing signal RX corresponding thereto may bethe longest, for example. Accordingly, in this case, the RC delay andsignal attenuation may be the greatest, the sensing capacitor C_M maynot be sufficiently charged and discharged, and the intensity of thesensing signal RX may be the smallest.

FIG. 3A is a drawing illustrating intensity of a sensing signal based ona frequency of a touch driving signal.

First, referring to FIGS. 1 and 3A, a first curve CURVE1 represents theintensity of a sensing signal (i.e., sensing signal received by thesensing unit RXD) based on the frequency of the first touch drivingsignal TX1. Here, the first touch driving signal TX1 may be provided tothe first driving electrode IE1-1 through the first driving signal lineSL1-1. A second curve CURVE2 represents the intensity of a sensingsignal based on the frequency of the fifth touch driving signal TX5.Here, the fifth touch driving signal TX5 may be provided to the fifthdriving electrode IE1-5 through the fifth driving signal line SL1-5. Theamplitude of the first touch driving signal TX1 and the amplitude of thefifth touch driving signal TX5 may have constant or fixed valuesregardless of the frequency, and may be the same.

When the frequency increases to a point adjacent to the first referencefrequency FREQ_REF1 along the first curve CURVE1, the intensity of thesensing signal may decrease. In a section where the frequency is smallerthan the first reference frequency FREQ_REF1, the intensity of thesensing signal is maintained at the reference strength INT_REF, and at apoint where the frequency is the same as the first reference frequencyFREQ_REF1, the intensity of the sensing signal may have the firststrength INT1, and may be changed by about −3 decibels (dB) based on thereference strength INT_REF. That is, the first reference frequencyFREQ_REF1 may be a frequency (e.g., cut-off frequency) at which theintensity of the sensing signal based on the first touch driving signalTX1 decreases to a half. In addition, as the frequency becomes greaterthan the first reference frequency FREQ_REF1, the sensing capacitancemay not be sufficiently charged and discharged, and the intensity of thesensing signal may decrease. In an embodiment, at a point where thefrequency is the same as the second reference frequency FREQ_REF2, theintensity of the sensing signal may have a second intensity INT2 smallerthan the first intensity INT1, for example.

Accordingly, the frequency of the first touch driving signal TX1 may beset to be smaller than or equal to the first reference frequencyFREQ_REF1. As an area of the input sensing device ISU increases, thesensing time allocated to the first driving electrode IE1-1 decreases,and the frequency of the first touch driving signal TX1 may decrease. Inthis case, the frequency of the first touch driving signal TX1 may havethe same frequency as the first reference frequency FREQ_REF1 atmaximum.

Similarly, when the frequency increases to a point adjacent to thesecond reference frequency FREQ_REF2 along the second curve CURVE2, theintensity of the sensing signal may decrease. Since the RC delay of thefifth touch driving signal TX5 is smaller than the RC delay of the firsttouch driving signal TX1, a cut-off frequency (i.e., second referencefrequency FREQ_REF2) for the fifth touch driving signal TX5 may begreater than a cut-off frequency (i.e., first reference frequencyFREQ_REF1) for the first touch driving signal TX1. Accordingly, thefrequency of the fifth touch driving signal TX5 may be set to be smallerthan or equal to the second reference frequency FREQ_REF2.

In this way, in consideration of a change in the intensity of thesensing signal due to the RC delay of each of the touch driving signalsTX1 to TX5 provided to the driving electrodes IE1-1 to IE1-5, thefrequency of each of the touch driving signals TX1 to TX5 may be set.

FIG. 3B is a drawing illustrating an embodiment of a touch drivingsignal generated by a driving signal generator included in the inputsensing device of FIG. 1 .

Referring to FIGS. 1, 3A, and 3B, the vertical synchronization signalVsync may be provided to the input sensing device ISU (or input sensingcircuit IS-C) from an external (e.g., host system such as an applicationprocessor), and may define a start of one frame. That is, a periodT_Vsync of the vertical synchronization signal Vsync may be equal to oneframe. In an embodiment, the period T_Vsync (or one frame) of thevertical synchronization signal Vsync may be about 16.6 milliseconds(ms), for example. During one frame, the input sensing device ISU maysupply the touch driving signals TX1 to TX5 to the driving electrodesIE1-1 to IE1-5 to perform an operation of determining whether a touch isinput to the entire input sensing panel ISP at least once (e.g., twice).For reference, as will be described later with reference to FIG. 18 ,when the input sensing device ISU is coupled with or unitary with thedisplay device, or included in the display device, data signals aresequentially written to pixels in the display device during one frame,and one frame image may be displayed.

The horizontal synchronization signal Hsync may be provided from anexternal (e.g., host system such as an application processor) to thedisplay device. The horizontal synchronization signal Hsync may define asection in which each of the horizontal line images included in oneframe image is output. The period T_Hsync of the horizontalsynchronization signal Hsync may be defined as one horizontal time 1H,and the horizontal line images may be sequentially output or displayedfor each one horizontal time 1H. In an embodiment, the period T_Hsync(or 1H) of the horizontal synchronization signal Hsync may be about 5.63microseconds (μs), for example.

The horizontal synchronization signal Hsync may be not provided to theinput sensing device ISU, but may act as noise in the input sensingdevice ISU.

Since the touch driving signals TX1 to TX5 generated by the inputsensing device ISU include a sinusoidal wave, noise due to thehorizontal synchronization signal Hsync may be easily removed from thesensing signals. In addition, noise may be more easily removed throughan analog front-end (i.e., fully differential analog front-end)described later. Accordingly, the frequencies of the touch drivingsignals TX1 to TX5 may be set asynchronously with the horizontalsynchronization signal Hsync.

That is, the touch driving signals TX1 to TX5 change irrespective of thehorizontal synchronization signal Hsync, and for example, the periods ofthe touch driving signals TX1 to TX5 may be about 5 μs, about 4 μs, andabout 2.9 μs (or, the touch driving signals TX1 to TX5 have frequenciesof about 200 kilohertz (KHz), about 250 KHz, and about 350 kHz), and maybe different from the period T_Hsync of the horizontal synchronizationsignal Hsync or a multiple thereof.

As described with reference to FIG. 3A, since the touch driving signalsTX1 to TX5 are set in consideration of only the change in the intensityof the sensing signal due to the RC delay, at least one of the touchdriving signals TX1 to TX5 may have a period smaller than the periodT_Hsync of the horizontal synchronization signal Hsync, or at least oneof the touch driving signals TX1 to TX5 may have a period greater thanthe period T_Hsync of the horizontal synchronization signal Hsync.

In an embodiment, all of the touch driving signals TX1 to TX5 may have aperiod smaller than the period T_Hsync of the horizontal synchronizationsignal Hsync, similar to the period T_TX_REF1 of the first referencetouch driving signal TX_REF1, for example. As another example, all ofthe touch driving signals TX1 to TX5 may have a period greater than theperiod T_Hsync of the horizontal synchronization signal Hsync, similarto the period T_TX_REF2 of the second reference touch driving signalTX_REF2. As another example, the period of the fifth touch drivingsignal TX5 may be set similar to the period T_TX_REF1 of the firstreference touch driving signal TX_REF1, and the period of the firsttouch driving signal TX1 may be set similar to the period T_TX_REF2 ofthe second reference touch driving signal TX_REF2.

FIGS. 3C and 3D are drawings illustrating another embodiment of a touchdriving signal generated by a driving signal generator included in theinput sensing device of FIG. 1 .

Referring to FIGS. 1, 3A, 3B, and 3C, the fifth touch driving signal TX5may be the same as the first reference touch driving signal TX_REF1. Asize (or amplitude) of the first reference touch driving signal TX_REF1is defined as one. In an embodiment, the frequency of the firstreference touch driving signal TX_REF1 may be greater than or equal tothe first reference frequency FREQ_REF1, and may be smaller than thesecond reference frequency FREQ_REF2, for example. In this case, theintensity of the sensing signal corresponding to the fifth touch drivingsignal TX5 may not decrease.

The first touch driving signal TX1 may be the same as the secondreference touch driving signal TX_REF2. The size of the second referencetouch driving signal TX_REF2 may be the same as the size of the firstreference touch driving signal TX_REF1.

In an embodiment, it is assumed that the frequency of the first touchdriving signal TX_REF1 is the same as the first reference frequencyFREQ_REF1, for example. In this case, the intensity of the sensingsignal corresponding to the first touch driving signal TX1 may decreaseto a half.

Accordingly, the first touch driving signal TX1 may be set to have arelatively large size (or amplitude), such as the third reference touchdriving signal TX_REF3. The frequency of the third reference touchdriving signal TX_REF3 may be the same as the frequency of the secondreference touch driving signal TX_REF2, but the size (or amplitude) ofthe third reference touch driving signal TX_REF3 may be twice the sizeof the second reference touch driving signal TX_REF2. In this case, theintensity of the sensing signal corresponding to the first touch drivingsignal TX1 may be the same as or similar to the intensity of the sensingsignal corresponding to the fifth touch driving signal TX5.

When the sensing time allocated to the first driving electrode IE1-1 towhich the first touch driving signal TX1 is applied decreases due to anenlargement of the input sensing device ISU, the frequency of the firsttouch driving signal TX1 may be set to the first reference frequencyFREQ_REF1 (or frequency at which the intensity decreases). In this case,the size of the first touch driving signal TX1 is set to be relativelyhigh, so that a decrease in the intensity of the sensing signal may becompensated.

That is, the input sensing device ISU may set the touch driving signalsTX1 to TX5 to have different sizes from one another as well as differentfrequencies from one another.

As will be described with reference to FIG. 10 , in order to reducepower consumption, the input sensing circuit IS-C may perform a samplingoperation on the touch driving signals TX1 to TX5 only in a portion ofthe sampling sections. Correspondingly, at least one of the touchdriving signals TX1 to TX5, such as the fourth reference touch drivingsignal TX_REF4 shown in FIG. 3D, may have a relatively high frequencyand a relatively large amplitude only in a section P_SA in which thesampling operation is performed, and may have a relatively smallfrequency and a relatively small amplitude in a section P_NSA in whichthe sampling operation is not performed.

That is, the input sensing device ISU may generate the touch drivingsignals TX1 to TX5 by combining different frequencies and differentamplitudes from one another.

As described with reference to FIGS. 3C and 3D, the touch drivingsignals TX1 to TX5 may have different amplitudes as well as differentfrequencies, and may also have a waveform in which different frequenciesand different amplitudes are combined.

FIGS. 4A to 4C are drawings illustrating embodiments of touch drivingsignals generated by a driving signal generator included in the inputsensing device of FIG. 1 . In FIGS. 4A to 4C, for convenience ofdescription, only some of the touch driving signals TX1 to TX5 areillustrated, but embodiments of FIGS. 4A to 4C may be applied to all ofthe touch driving signals TX1 to TX5.

Referring to FIGS. 1, 3B, and 4A, in a section in which a pulse of thevertical synchronization signal Vsync occurs, the touch driving signalsTX1 to TX5 may have a reference value (or a direct current (“DC”)voltage). In an embodiment, the driving signal generator TXD may notoutput the touch driving signals TX1 to TX5 in the section (i.e., beforethe first section P1) in which the pulse of the vertical synchronizationsignal Vsync occurs, or may output the touch driving signals TX1 to TX5having a predetermined value, e.g., zero volt (V).

Immediately before a rising edge of the vertical synchronization signalVsync occurs (or before a pulse of a logical high level occurs), thetouch driving signals TX1 to TX5 have a reference value, and after afalling edge of the vertical synchronization signal Vsync occurs (orafter the pulse ends), the touch driving signals TX1 to TX5 may includea sinusoidal wave.

For reference, since the period T_Hsync of the horizontalsynchronization signal Hsync is relatively short, noise (e.g., noisehaving a relatively high frequency) caused by the horizontalsynchronization signal Hsync may be effectively filtered through theanalog front-ends AFE1 to AFE4. However, since the period of thevertical synchronization signal Vsync is relatively long, noise (i.e.,noise having a relatively low frequency) caused by the verticalsynchronization signal Vsync may not be filtered through the analogfront-ends AFE1 to AFE4. Accordingly, the driving signal generator TXDmay generate the touch driving signals TX1 to TX5 that are synchronizedwith the vertical synchronization signal Vsync, that is, avoids thepulse of the vertical synchronization signal Vsync.

In an embodiment, the touch driving signals TX1 to TX5 may sequentiallyhave valid signals (i.e., sinusoidal wave) during one frame 1 FRAME.That is, the input sensing device ISU may provide the touch drivingsignals TX1 to TX5 to the driving electrodes IE1-1 to IE1-5 in asequential driving method.

One frame 1 FRAME may sequentially include the first to fifth sectionsP1 to P5.

The first touch driving signal TX1 provided to the first drivingelectrode IE1-1 in the first section P1 may include a sinusoidal wavehaving a first period T_TX1.

The second touch driving signal TX2 provided to the second drivingelectrode IE1-2 in the second section P2 may include a sinusoidal wavehaving a second period T_TX2. The second period T_TX2 may be smallerthan the first period T_TX1.

The fifth touch driving signal TX5 provided to the fifth drivingelectrode IE1-5 in the fifth section P5 may include a sinusoidal wavehaving a fifth period T_TX5. The fifth period T_TX5 may be smaller thanthe second period T_TX2.

That is, the input sensing device ISU may sequentially provide the touchdriving signals TX1 to TX5 having different periods (or frequencies) tothe driving electrodes IE1-1 to IE1-5 in different sections.

In an embodiment, the first to fifth sections P1 to P5 may have the samewidth. In another embodiment, the first to fifth sections P1 to P5 mayhave different widths. In an embodiment, the width of the first sectionP1 corresponding to the first period T_TX1 of the first touch drivingsignal TX1 may be the largest, and the width of the fifth section P5corresponding to the fifth period T_TX5 of the fifth touch drivingsignal TX5 may be the smallest, for example. In this case, the totalsensing time of the input sensing device ISU may decrease. In analternative embodiment, when the total sensing time is fixed, the touchdriving signals TX1 to TX5 may have a relatively low frequency (i.e.,frequency corresponding to a relatively high sensing sensitivity).

In an embodiment, the touch driving signals TX1 to TX5 may have a validsignal (i.e., sinusoidal wave) sequentially two or more times during oneframe 1 FRAME. In an embodiment, the touch driving signals TX1 to TX5may include a valid signal (i.e., sinusoidal wave) in two or moresections that are sequentially discontinuous from each other (i.e.,separated from each other) during one frame 1 FRAME, for example. Thatis, the input sensing device ISU may provide the touch driving signalsTX1 to TX5 to the driving electrodes IE1-1 to IE1-5 two or more times ina sequential driving method.

One frame 1 FRAME may further include sixth to tenth sections P6 to P10sequentially.

The first touch driving signal TX1 provided to the first drivingelectrode IE1-1 in the sixth section P6 may include a sinusoidal wavehaving a first period T_TX1.

The second touch driving signal TX2 provided to the second drivingelectrode IE1-2 in the seventh section P7 may include a sinusoidal wavehaving a second period T_TX2.

The fifth touch driving signal TX5 provided to the fifth drivingelectrode IE1-5 in the tenth section P10 may include a sinusoidal wavehaving a fifth period T_TX5.

In FIG. 4A, the touch driving signals TX1 to TX5 are described to havedifferent periods (or frequencies), but the touch driving signals TX1 toTX5 are not limited thereto.

Referring to FIGS. 1 and 4B, the first touch driving signal TX1 providedto the first driving electrode IE1-1 in the first section P1 may includea sinusoidal wave having a first period T_TX1.

The second touch driving signal TX2 provided to the second drivingelectrode IE1-2 in the second section P2 may include a sinusoidal wavehaving a second period T_TX2. Here, the second period T_TX2 may be thesame as the first period T_TX1.

That is, a touch driving signal having the same period may be providedto the first driving electrode IE1-1 and the second driving electrodeIE1-2 included in the first area A1.

The fourth touch driving signal TX4 provided to the fourth drivingelectrode IE1-4 in the fourth section P4 may include a sinusoidal wavehaving a fourth period T_TX4. The fourth period T_TX4 may be smallerthan the second period T_TX2.

The fifth touch driving signal TX5 provided to the fifth drivingelectrode IE1-5 in the fifth section P5 may include a sinusoidal wavehaving a fifth period T_TX5. Here, the fifth period T_TX5 may be thesame as the fourth period T_TX4.

That is, a touch driving signal having the same period may be providedto the fourth driving electrode IE1-4 and the fifth driving electrodeIE1-5 included in the second area A2.

In FIGS. 4A and 4B, the input sensing device ISU is described to providethe touch driving signals TX1 to TX5 to the driving electrodes IE1-1 toIE1-5 in a sequential driving method, but it is not limited thereto.

Referring to FIGS. 1 and 4C, the touch driving signals TX1 to TX5 maysimultaneously have valid signals (i.e., sinusoidal waves) during oneframe 1 FRAME. That is, the input sensing device ISU may provide thetouch driving signals TX1 to TX5 to the driving electrodes IE1-1 toIE1-5 in a simultaneous driving method.

The second period T_TX2 of the second touch driving signal TX2 may besmaller than the first period T_TX1 of the first touch driving signalTX1, and the fifth period T_TX5 of the fifth touch driving signal TX5may be smaller than the second period T_TX2 of the second touch drivingsignal TX2. That is, the touch driving signals TX1 to TX5 may havedifferent periods (or frequencies).

In this case, the input sensing device ISU (or sensing unit RXD) maydetermine whether a touch has occurred or calculate a location where thetouch has occurred through frequency analysis. In an embodiment, thesensing unit RXD may obtain a frequency size of the sensing signals byperforming fast Fourier transform on the sensing signals, and maycalculate a touch location based on a change in the frequency size, forexample. In an embodiment, when a frequency size corresponding to thefirst period T_TX1 is smaller in the sensing signal received from thefirst sensing electrode IE2-1, the sensing unit RXD may determine that atouch has occurred in a region where the first sensing electrode IE2-1and the first driving electrode IE1-1 intersect, for example.

As described with reference to FIGS. 4A to 4C, the input sensing deviceISU may provide the touch driving signals TX1 to TX5 to the drivingelectrodes IE1-1 to IE1-5 in the sequential driving method or thesimultaneous driving method. Also, the touch driving signals TX1 to TX5may have different frequencies, or some of the touch driving signals TX1to TX5 may have the same frequency.

FIG. 5 is a block diagram illustrating an embodiment of a driving signalgenerator included in the input sensing device of FIG. 1 .

Referring to FIGS. 1 and 5 , the driving signal generator TXD mayinclude a waveform generator WG, a frequency modulator FM, and ademultiplexer DEMUX.

The waveform generator WG may generate a reference signal. In anembodiment, the waveform generator WG may be implemented as a generaloscillation circuit or a function generator, for example. The referencesignal may include a sinusoidal wave, and a frequency of the referencesignal may be greater than or equal to the frequency of the touchdriving signals TX1 to TX5.

The frequency modulator FM may generate touch driving signals TX1 to TX5by frequency-modulating the reference signal.

In an embodiment, the frequency modulator FM may generate the touchdriving signals TX1 to TX5 by frequency division of the referencesignal. In an embodiment, the frequency modulator FM may generate thefirst touch driving signal TX1 by dividing the reference signal by six,and may generate the fifth touch driving signal TX5 by dividing thereference signal by three. Divided values for each of the touch drivingsignals TX1 to TX5 may be preset in the manufacturing process of theinput sensing device ISU (and a display device including the same), andmay be stored in a separate memory device, for example.

In another embodiment, the frequency modulator FM may generate the touchdriving signals TX1 to TX5 by adding an offset frequency to thefrequency of the reference signal. In an embodiment, the frequencymodulator FM may generate the first touch driving signal TX1 by addingoffset frequencies such as 0 KHz, 50 KHz, 100 KHz, and the like to thereference signal, and may generate the fifth touch driving signal TX5 byadding offset frequencies such as 100 KHz, 150 KHz, 200 KHz, and thelike to the reference signal, for example. The offset frequency for eachof the touch driving signals TX1 to TX5 may be preset during amanufacturing process of the input sensing device ISU (and a displaydevice including the same), and may be stored in a separate memorydevice. The touch driving signals TX1 to TX5 generated based on theoffset frequency may have a frequency more optimized for the inputsensing device ISU than the touch driving signals TX1 to TX5 generatedthrough frequency division.

In an embodiment, the frequency modulator FM may sequentially generatethe touch driving signals TX1 to TX5. Referring to FIG. 4A, for example,the frequency modulator FM may generate the first touch driving signalTX1 in the first section P1, and may generate the fifth touch drivingsignal TX5 in the fifth section P5.

In this case, the demultiplexer DEMUX may transmit the first touchdriving signal TX1 to the first driving signal line SL1-1 (and the firstdriving electrode IE1-1) in the first section P1, and may transmit thefifth touch driving signal TX5 to the fifth driving signal line SL1-5(and the fifth driving electrode IE1-5) in the fifth period P5.

In another embodiment, the frequency modulator FM may simultaneouslygenerate the touch driving signals TX1 to TX5. Referring to FIG. 4C, forexample, the frequency modulator FM simultaneously generates the firsttouch driving signal TX1 to the fifth touch driving signal TX5, and mayprovide the first touch driving signal TX1 to the fifth touch drivingsignal TX5 to the first driving signal line SL1-1 to the fifth drivingsignal line SL1-5, respectively. In this case, the demultiplexer DEMUXmay be omitted.

As described with reference to FIG. 5 , the driving signal generator TXDmay generate the touch driving signals TX1 to TX5 having differentfrequencies by frequency-modulating the reference signal.

FIGS. 6A and 6B are block diagrams illustrating an embodiment of ananalog front end included in the input sensing device of FIG. 1 . FIG.7A is a circuit diagram illustrating an embodiment of a charge amplifierincluded in the analog front end of FIG. 6A. FIG. 7B is a drawingillustrating an embodiment of signals for explaining an operation of theanalog front end of FIG. 6A. In FIG. 7B, signals applied to the analogfront-end AFEn of FIG. 6A or generated in the analog front-end AFEn areshown in the frequency domain.

Referring to FIGS. 1 and 6A, since the analog front-ends AFE1 to AFE4are equivalent to each other, the analog front-end AFEn (here n is apositive integer) will be described as representative of the analogfront-ends AFE1 to AFE4.

The analog front-end AFEn may include a charge amplifier CA (or firstcharge amplifier), a band pass filter BPF, a mixer MX, a low pass filterLPF, and an analog-to-digital converter ADC.

The charge amplifier CA may receive an n-th sensing signal RXn providedthrough the n-th sensing signal line SL2-n and an n+1-th sensing signalRXn+1 provided through the n+1-th sensing signal line SL2-(n+1), and maydifferentially amplifying the n-th sensing signal RXn and the n+1-thsensing signal RXn+1 to output a first differential signal CA_OUT1 andsecond differential signal CA_OUT2 complementary to each other.

In an embodiment, the charge amplifier CA may be implemented as a fullydifferential amplifier. A typical differential amplifier maydifferentiate two input signals to output one signal, and a fullydifferential amplifier may be defined as a differential amplifier thatdifferentials two input signals to output two differential signals(i.e., complementary signals). The charge amplifier CA implemented asthe fully differential amplifier may maximize a size of sensing signalsin relation to an analog-to-digital converter ADC (e.g., a differentialanalog-to-digital converter that differentials two analog signals tooutput a digital value).

Referring to FIG. 7A, the charge amplifier CA may include an amplifierAMP, a first capacitor C1, a first resistor R1, a second capacitor C2,and a second resistor R2.

The amplifier AMP may include a second input terminal IN_P (i.e., +inputterminal), a first input terminal IN_N (i.e., −input terminal), a firstoutput terminal OUT_P (i.e., +output terminal), and a second outputterminal OUT_N (i.e., −output terminal). In some cases, the amplifierAMP may include a first sub-amplifier including input/output terminalscorresponding to the second input terminal IN_P, the first inputterminal IN_N, and the first output terminal OUT_P, and a secondsub-amplifier including input/output terminals corresponding to thesecond input terminal IN_P, the first input terminal IN_N, and thesecond output terminal OUT_N.

The first input terminal IN_N of the amplifier AMP may be connected tothe n-th sensing signal line SL2-n, and the n-th sensing signal RXn maybe applied to the first input terminal IN_N of the amplifier AMP. Thesecond input terminal IN_P of the amplifier AMP may be connected to then+1-th sensing signal line SL2-(n+1), and the n+l-th sensing signalRXn+1 may be applied to the second input terminal IN_P of the amplifierAMP.

The first capacitor C1 and the first resistor R1 may be connected inparallel between the first input terminal IN_N and the first outputterminal OUT_P of the amplifier AMP. Therefore, a first differentialsignal CA_OUT1 corresponding to a difference between the n-th sensingsignal RXn and the n+1-th sensing signal RXn+1 may be output through thefirst output terminal OUT_P of the amplifier AMP.

Similarly, the second capacitor C2 and the second resistor R2 may beconnected in parallel between the second input terminal IN_P and thesecond output terminal OUT_N of the amplifier AMP. Accordingly, a seconddifferential signal CA_OUT2 corresponding to a difference between then+1-th sensing signal RXn+1 and the n-th sensing signal RXn may beoutput through the second output terminal OUT_N of the amplifier AMP.The second differential signal CA_OUT2 may have a waveform in which thefirst differential signal CA_OUT1 is inverted.

The charge amplifier CA may remove alternating current (“AC”) offset andcommon noise by outputting the first differential signal CA_OUT1 and thesecond differential signal CA_OUT2 in a differential method.

Referring back to FIG. 6A, the band pass filter BPF may select onlysignals in a predetermined frequency band of each of the firstdifferential signal CA_OUT1 and the second differential signal CA_OUT2,and may output the first filtered signal BPF_OUT1 and the secondfiltered signal BPF_OUT2.

Referring to FIG. 7B, the touch signal TS has a frequency within areference bandwidth (e.g., −ωB to ωB) based on the driving frequency (orsensing period) of the input sensing circuit IS-C (refer to FIG. 1 ).The sensing signal RX provided to the analog front-end AFEn from thesensing electrodes IE2-1 to IE2-4 (refer to FIG. 1 ) may be modulated bythe touch driving signal TX, and may have a frequency within a referencebandwidth (2ω0) based on a frequency (ω0) of the touch driving signalTX. The sensing signal RX may include a negative frequency component(e.g. −ω0), but the negative frequency component may have the same sizeas a positive frequency component and may have a phase difference of 180degrees from a positive frequency component, and the negative frequencycomponent has no physically meaning. Therefore, it is not considered.The band pass filter BPF may have a first transfer function F_BPFcorresponding to the frequency band of the sensing signal RX, and mayamplify only a signal in the corresponding frequency band. In anembodiment, the band pass filter BPF may be implemented including adifferential amplifier (or fully differential amplifier), a capacitor,and a resistor, and may amplify only a signal corresponding to thefrequency band (e.g., 200 KHz to 350 KHz) of the touch driving signal TX(or touch driving signals TX1 to TX5), for example.

Referring back to FIG. 6A, the band pass filter BPF may selectivelyamplify the first differential signal CA_OUT1 to output a first filteredsignal BPF_OUT1, and may selectively amplify the second differentialsignal CA_OUT2 to output a second filtered signal BPF_OUT2. In anembodiment, the band pass filter BPF may selectively amplify the firstdifferential signal CA_OUT1 applied to a negative input terminal of thefully differential amplifier to output the first filtered signalBPF_OUT1 through a positive output terminal of the fully differentialamplifier, and may selectively amplify the second differential signalCA_OUT2 applied to the positive input terminal of the fully differentialamplifier to output the second filtered signal BPF_OUT2 through thenegative output terminal of the fully differential amplifier, forexample.

The second filtered signal BPF_OUT2 may have a waveform in which thefirst filtered signal BPF_OUT1 is inverted.

The mixer MX may change a frequency of each of the first filtered signalBPF_OUT1 and the second filtered signal BPF_OUT2 to output a firstdemodulated signal MX_OUT1 and a second demodulated signal MX_OUT2. Inan embodiment, the mixer MX may demodulate the first filtered signalBPF_OUT1 to output a first demodulated signal MX_OUT1, and maydemodulate the second filtered signal BPF_OUT2 to output a seconddemodulated signal MX_OUT2, for example.

In an embodiment, the mixer MX may be implemented as a chopping circuit(or chopper) including two input terminals and two output terminals, andmay generate the first demodulated signal MX_OUT1 and the seconddemodulated signal MX_OUT2 by alternately connecting the first filteredsignal BPF_OUT1 and second filtered signal BPF_OUT2 provided to the twoinput terminals to the two output terminals, for example. That is, themixer MX may extract the touch signal TS (refer to FIG. 7B) from thefirst filtered signal BPF_OUT1 and the second filtered signal BPF_OUT2.

Referring to FIG. 7B, the mixer MX may convert a signal in a relativelyhigh frequency band (i.e., signal in a frequency band corresponding tothe band pass filter BPF) into a demodulated signal MX_OUT in a lowfrequency band (i.e., signal in a frequency band corresponding to thetouch signal TS). In addition, the mixer MX may convert noise in arelatively low frequency band into high frequency noise NS in a highfrequency band. For reference, a low frequency noise (e.g., noisereferred to as “1/f noise”) may be basically generated in semiconductordevices (e.g., transistors) constituting the analog front-end AFEn, andthe mixer MX may move the low frequency noise to the high frequency bandthrough a chopping operation.

Referring back to FIG. 6A, a low pass filter LPF may filter noisedistributed in the high frequency band of each of the first demodulatedsignal MX_OUT1 and the second demodulated signal MX_OUT2 to output afirst output signal LPF_OUT1 (or third filtered signal) and a secondoutput signal LPF_OUT2 (or fourth filtered signal).

In an embodiment, the low pass filter LPF may be implemented including adifferential amplifier (or fully differential amplifier), a resistor,and a capacitor, and may amplify only a signal in a relatively lowfrequency band, for example. The low pass filter LPF may filter noise ofthe first demodulated signal MX_OUT1 to output the first output signalLPF_OUT1, and may filter noise of the second demodulated signal MX_OUT2to output the second output signal LPF_OUT2. In an embodiment, the lowpass filter LPF may filter the noise of the first demodulated signalMX_OUT1 applied to the negative input terminal of the fully differentialamplifier to output the first output signal LPF_OUT1 through thepositive output terminal of the fully differential amplifier, and mayfilter the noise of the second demodulated signal MX_OUT2 applied to thepositive input terminal of the fully differential amplifier to outputthe second output signal LPF_OUT2 through the positive output terminalof the fully differential amplifier. The second output signal LPF_OUT2may have a polarity different from the first output signal LPF_OUT1, forexample.

Referring to FIG. 7B, the low pass filter LPF has a second transferfunction F_LPF corresponding to the frequency band of the touch signalTS, and for example, a gain GAIN_LPF of the second transfer functionF_LPF may be about 2 in a frequency band (DB or less. In this case, thelow pass filter LPF may amplify only the demodulated signal MX_OUT inthe low frequency band and output it as an output signal LPF_OUT.

As described above, the band pass filter BPF, the mixer MX, and the lowpass filter LPF may implement the function of the demodulator, and mayrestore or extract only a signal (i.e., first output signal LPF_OUT1 andsecond output signal LPF_OUT2) corresponding to the touch driving signalTX from the n-th sensing signal RXn and the n+1-th sensing signal RXn+1.

The analog-to-digital converter ADC may receive the first output signalLPF_OUT1 and the second output signal LPF_OUT2, and may provide asensing value (or differential output value) corresponding to adifference (e.g., |LPF_OUT1−LPF_OUT2|) between the first output signalLPF_OUT1 and the second output signal LPF_OUT2 to the signal processingunit DSP. In an embodiment, the analog-to-digital converter ADC mayconvert the first output signal LPF_OUT1 into a first output value, mayconvert the second output signal LPF_OUT2 into a second output value,and may differentially compare the first output value and the secondoutput value to output a sensing value, for example.

The analog-to-digital converter ADC may sample each of the first outputsignal LPF_OUT1 and the second output signal LPF_OUT2 four or more timesduring a preset reference time (e.g., one horizontal time 1H), and maysum the sampled value to output a sensing value.

In an embodiment, the analog-to-digital converter ADC may performsampling for each of the sensing signals corresponding to the touchdriving signals TX1 to TX5 (refer to FIG. 1 ) at the same number ofsampling times. The sampling operation of the analog-to-digitalconverter ADC will be described later with reference to FIGS. 8, 9A, 9B,and 10 .

The analog front-end AFEn may further include a second charge amplifierCA2.

As shown in FIG. 6B, the second charge amplifier CA2 may be connected toan output terminal (or rear terminal) of the analog-to-digital converterADC, may amplify the sensing value output from the analog-to-digitalconverter ADC, and may provide the amplified sensing value to the signalprocessing unit DSP. In this case, the signal processing unit DSP maymore easily determine whether a touch has been performed using theamplified sensing value.

As described with reference to FIGS. 6A, 6B, 7A, and 7B, the analogfront-end AFEn may remove noise (e.g., noise due to the horizontalsynchronization signal Hsync described with reference to FIG. 3B) fromthe n-th sensing signal RXn and the n+1-th sensing signal RXn+1 by thecharge amplifier CA, the band pass filter BPF, the mixer MX, and the lowpass filter LPF. In addition, the analog front-end AFEn may beimplemented as a fully differential circuit (or fully differentialanalog front-end) that maintains and outputs two differential signalsfrom the charge amplifier CA to a front terminal (i.e., low pass filterLPF) of the analog-to-digital converter ADC. The analog front-end AFEnmay provide two differential signals to the analog-to-digital converterADC, thereby doubling a dynamic range of the analog-to-digital converteror a range of use of the dynamic range, and improving touch sensingsensitivity.

FIG. 8 is a drawing illustrating a sampling operation of ananalog-to-digital converter included in the analog front end of FIG. 6A.FIGS. 9A and 9B are drawings illustrating an embodiment of sensingvalues based on the number of sampling times of an analog-to-digitalconverter included in the analog front end of FIG. 6A. FIG. 10 is adrawing illustrating another embodiment of an operation of ananalog-to-digital converter included in the analog front end of FIG. 6A.

The first and second output signals LPF_OUT1 and LPF_OUT2 (e.g.,waveforms and periods thereof) described with reference to FIG. 6A maybe substantially the same as or similar to the sensing signals RXn andRXn+1 from which noise is removed. In addition, a signal (or namethereof) provided to the analog-to-digital converter ADC may changeaccording to a configuration (e.g., configuration for removing noise)inside the analog front-end AFEn. Therefore, for convenience ofdescription, the sampling operation of the analog-to-digital converterADC will be described based on the sensing signal applied to the analogfront-end AFEn.

First, referring to FIGS. 1, 6A, and 8 , the first sensing signal RX_1may correspond to the first touch driving signal TX1 provided to thefirst driving electrode IE1-1. In an embodiment, the first sensingsignal RX_1 may be a sensing signal provided to the analog front-endAFEn through the first sensing electrode IE2-1 in response to the firsttouch driving signal TX1, for example. Since the first sensing signalRX_1 has a relatively small frequency corresponding to a first frequencyFREQ1 of the first touch driving signal TX1, for convenience ofdescription, the first sensing signal RX_1 may be represented as sin X.

The second sensing signal RX_2 may correspond to the fifth touch drivingsignal TX5 provided to the fifth driving electrode IE1-5. In anembodiment, the second sensing signal RX_2 may be a sensing signalprovided to the analog front-end AFEn through the first sensingelectrode IE2-1 in response to the fifth touch driving signal TX5, forexample. Since the second sensing signal RX_2 has a relatively highfrequency corresponding to a fifth frequency FREQ5 of the fifth touchdriving signal TX5, for convenience of description, the second sensingsignal RX_2 may be represented as sin 2X.

In an embodiment, the analog-to-digital converter ADC (or analogfront-end AFEn) may sample the first sensing signal RX_1 and the secondsensing signal RX_2 at the same number of sampling times.

In an embodiment, the analog-to-digital converter ADC may sample thefirst sensing signal RX_1 and the second sensing signal RX_2 at N times(here N is an integer greater than 4) during a reference time (e.g., 1H,or one period of the first touch driving signal TX1). As shown in FIG.9A, when the number of sampling times is 4 or less, the sampled valuemay be zero, and in this case, a touch input may not be sensed.

As shown in FIG. 8 , the analog-to-digital converter ADC may sample thefirst sensing signal RX_1 at 16 times and the second sensing signal RX_2at 16 times during one period of the first touch driving signal TX1.

In an embodiment, the analog-to-digital converter ADC may output asensing value by summing sampled values during the reference time. Inthis case, the first sensing value S_RX1 (refer to FIG. 9A) for thefirst sensing signal RX_1 may be different from the second sensing valueS_RX2 (refer to FIG. 9A) for the second sensing signal RX_2. In anembodiment, the first sensing value S_RX1 may be greater than the secondsensing value S_RX2, for example.

Referring to FIG. 9A, when the number of sampling times is 4, adifference Δ between the first sensing value S_RX1 and the secondsensing value S_RX2 may be 2. In an embodiment, the analog-to-digitalconverter ADC may sample values of 0, 1, 0, and 1 at points TP1, TP2,TP3, TP4 (refer to FIG. 8 ) where phases of the first sensing signalRX_1 are 0, 90, 180, 270, respectively, and may output a first sensingvalue S_RX1 having a value of 2 by summing the sampled values, forexample. Similarly, the analog-to-digital converter ADC may samplevalues of 0, 0, 0, and 0 at points TP1, TP2, TP3, TP4 (refer to FIG. 8 )where phases of the second sensing signal RX_2 are 0, 180, 360 (or 0),540 (or 180), respectively, and may output a second sensing value S_RX2having a value of 0 by summing the sampled values. Accordingly, when thenumber of sampling times is 4, the difference Δ between the firstsensing value S_RX1 and the second sensing value S_RX2 may be 2.

Similarly, when the number of sampling times is 8, the difference Δbetween the first sensing value S_RX1 and the second sensing value S_RX2may be 0.828 (i.e., 4.828-4), and may be smaller than the difference Δwhen the number of sampling times is 4. When the number of samplingtimes is 12, 36, 60, 72, 120, 180, and 360, the difference Δ between thefirst sensing value S_RX1 and the second sensing value S_RX2 is as shownin FIG. 9A. Therefore, description thereof will be omitted.

As shown in FIGS. 9A and 9B, as the number of sampling times increases,the difference Δ between the first sensing value S_RX1 and the secondsensing value S_RX2 decreases, but the first sensing value S_RX1 may bealways greater than the second sensing value S_RX2.

As described above with reference to FIGS. 2A and 2B, attenuation of thefirst touch driving signal TX1 (and the first sensing signal RX_1corresponding thereto) may be greater than attenuation of the fifthtouch driving signal TX5 (and the second sensing signal RX_2corresponding thereto). In order to compensate for an attenuationdifference between the attenuation of the first touch driving signal TX1and the attenuation of the fifth touch driving signal TX5, thedifference Δ between the first sensing value S_RX1 and the secondsensing value S_RX2 may be used. In other words, in order to compensatefor the relatively great attenuation of the first touch driving signalTX1, it may be considered to use the first sensing value S_RX1 that isgreater than the second sensing value S_RX2 by an attenuation value (orattenuation ratio) that the first touch driving signal TX1 is attenuatedinstead of adding a separate configuration, and the first sensing valueS_RX1 may be set to be greater than the second sensing value S_RX2 bythe attenuation value by adjusting the number of sampling times. Thatis, even when the first touch driving signal TX1 is relatively furtherattenuated, the first sensing value S_RX1 is relatively great at apredetermined number of sampling times corresponding thereto.Accordingly, the attenuation difference between the attenuation of thefirst touch driving signal TX1 and the attenuation of the fifth touchdriving signal TX5 may be automatically compensated by the difference Δbetween the first sensing value S_RX1 and the second sensing valueS_RX2.

To this end, the number of sampling times of the analog-to-digitalconverter ADC may be determined based on the attenuation differencebetween the attenuation of the first touch driving signal TX1 and theattenuation of the fifth touch driving signal TX5. Since the attenuationdifference is substantially proportional to the location (i.e., distancespaced apart from the input sensing circuit IS-C, or resistance valuecorresponding thereto) of the first driving electrode IE1-1 to which thefirst touch driving signal TX1 is applied, the number of sampling timesof the analog-to-digital converter ADC may be determined based on thelocation of the first driving electrode IE1-1. In an embodiment, as anarea of the input sensing panel ISP (refer to FIG. 1 ) becomes larger,the location of the first driving electrode IE1-1 may be farther fromthe input sensing circuit IS-C, and the number of sampling times of theanalog-to-digital converter ADC may be set to be relatively small, forexample. That is, the number of sampling times of the analog-to-digitalconverter ADC may be set in inverse proportion to an area of the inputsensing panel ISP.

In an embodiment, the attenuation difference between the attenuation ofthe first touch driving signal TX1 and the attenuation of the fifthtouch driving signal TX5 may be assumed to be 0.2, for example. In orderto set the number of sampling times of the analog-to-digital converterADC, the analog-to-digital converter ADC may perform sampling operationwith 60 sampling times at first. The difference Δ between the firstsensing value S_RX1 and the second sensing value S_RX2 corresponding tothe 60 sampling times may be smaller than the attenuation difference. Inthis case, the analog-to-digital converter ADC may reduce the number ofsampling times, and may again perform the sampling operation with, forexample, 36 sampling times. The difference Δ between the first sensingvalue S_RX1 and the second sensing value S_RX2 corresponding to the 36sampling times may be similar to the attenuation difference. In thiscase, the number of sampling times of the analog-to-digital converterADC may be set to 36 times. In this way, depending on the size (e.g.,large, medium, small) of the input sensing panel ISP, the number ofsampling times of the analog-to-digital converter ADC may be set to 36,60, and 72 times, respectively.

In an embodiment, the analog-to-digital converter ADC may perform thesampling operation only in a section in which the first sensing signalRX_1 has a predetermined phase.

Referring to FIG. 10 , the analog-to-digital converter ADC may performthe sampling operation only in sub-sections P_S1, P_S2, P_S3, and P_S4.In an embodiment, each of the first sub-section P_S1 and the thirdsub-section P_S3 may be a section in which a phase of the first sensingsignal RX_1 is 60 degrees to 120 degrees, for example. In the firstsub-section P_S1 and the third sub-section P_S3, the first sensingsignal RX_1 may have a positive maximum value (or maximum level). Thesecond sub-section P_S2 and the fourth sub-section P_S4 may be a sectionin which a phase of the first sensing signal RX_1 is 240 degrees to 300degrees. In the second sub-section P_S2 and the fourth sub-section P_S4,the first sensing signal RX_1 may have a negative maximum value.

In this case, the number of sampling times for the first sensing signalRX_1 may decrease from 16 times to 6 times based on one period of thefirst sensing signal RX_1.

In the first sub-section P_S1, the second sub-section P_S2, the thirdsub-section P_S3, and the fourth sub-section P_S4, the phase of thesecond sensing signal RX_2 may be 120 degrees to 240 degrees. In thefirst sub-section P_S1, the second sub-section P_S2, the thirdsub-section P_S3, and the fourth sub-section P_S4, the second sensingsignal RX_2 may not have a positive or negative maximum value, and mayhave a value of zero.

In this case, at the same sampling frequency, the difference Δ betweenthe first sensing value S_RX1 and the second sensing value S_RX2 may begreater.

That is, the analog-to-digital converter ADC may reduce the number ofsampling times by performing the sampling operation only in some sectionamong the entire sampling section while maintaining the samplingfrequency.

For reference, it may be a power loss for the analog-to-digitalconverter ADC to perform the sampling operation in the entire samplingsection (e.g., to sample a value of zero). Therefore, by performing thesampling operation only in some section among the entire samplingsection, the analog-to-digital converter ADC may reduce powerconsumption while maintaining the difference Δ between the first sensingvalue S_RX1 and the second sensing value S_RX2.

As described with reference to FIGS. 8, 9A, 9B, and 10 , ananalog-to-digital converter ADC (or analog front-end AFEn) may samplethe first sensing signal RX_1 and the second sensing signal RX_2 at thesame number of sampling times, respectively, and may sum the sampledvalues to output the first sensing value S_RX1 and the second sensingvalue S_RX2. The difference between the attenuation of the first touchdriving signal TX1 (and the first sensing signal RX_1 correspondingthereto) and the attenuation of the fifth touch driving signal TX5 (andthe second sensing signal RX_2 corresponding thereto) may be compensatedby the difference Δ between the first sensing value S_RX1 and the secondsensing value S_RX2. Accordingly, the touch sensing sensitivity may beuniform over the entire sensing area SA of the input sensing panel ISP.

In addition, by performing the sampling operation only in some sectionamong the entire sampling section, the analog-to-digital converter ADCmay reduce power consumption while maintaining the difference Δ betweenthe first sensing value S_RX1 and the second sensing value S_RX2.

FIG. 11 is a drawing illustrating another embodiment of an input sensingdevice.

Referring to FIGS. 1 and 11 , the input sensing device ISU may furtherinclude distribution circuits DC1, DC2, and DC3.

The distribution circuits DC1, DC2, and DC3 may be disposed between atleast some of the sensing electrodes IE2-1 to IE2-4 and the analogfront-ends AFE1 to AFE4, may generate a plurality of signals having thesame size (e.g., the same voltage level, or the same current amount)based on each of sensing signals provided from at least some of thesensing electrodes IE2-1 to IE2-4, and may distribute the generatedsignals to the analog front-ends AFE1 to AFE4. In an embodiment, thedistribution circuits DC1, DC2, and DC3 may include an amplifier, abuffer, and the like, and may amplify or mirror each of the sensingsignals and output them, for example.

In an embodiment, the first distribution circuit DC1 may receive asecond sensing signal provided from the second sensing electrode IE2-2,and may provide signals that is the same or has the same size as thesecond sensing signal to each of the first analog front-end AFE1 and thesecond analog front-end AFE2, for example. For reference, when thesecond sensing signal does not pass through the first distributioncircuit DC1, the second sensing signal may be simultaneously supplied tothe first analog front-end AFE1 and the second analog front-end AFE2,and a size (or maximum size, e.g., voltage level, or current amount) ofthe second sensing signal may be different from a size of the firstsensing signal (i.e., sensing signal provided from the first sensingelectrode IE2-1) due to a relative increase in a load for the secondsensing signal. Accordingly, the input sensing device ISU may providesignals being the same or having the same size as the second sensingsignal to the first analog front-end AFE1 and the second analogfront-end AFE2, respectively by the first distribution circuit DC1.

Similarly, the second distribution circuit DC2 may receive the thirdsensing signal provided from the third sensing electrode IE2-3, and mayprovide signals being the same or having the same size as the thirdsensing signal to the second analog front-end AFE2 and the third analogfront-end AFE3, respectively. The third distribution circuit DC3 mayreceive the fourth sensing signal provided from the fourth sensingelectrode IE2-4, and may provide signals being the same or having thesame size as the fourth sensing signal to the third analog front-endAFE3 and the fourth analog front-end AFE4, respectively.

FIG. 12 is a drawing illustrating an input sensing device. FIG. 13 is ablock diagram illustrating an embodiment of an analog front end includedin the input sensing device of FIG. 12 .

Referring to FIGS. 1 and 12 , except for the analog front-ends AFE1_0 toAFE4_0, the input sensing device ISU_0 may be substantially the same asor similar to the input sensing device ISU of FIG. 1 . Therefore,duplicate descriptions will be omitted.

The analog front-ends AFE1_0 to AFE4_0 may be connected to the sensingelectrodes IE2-1 to IE2-4 through the sensing lines SL2-1 to SL2-4,respectively, and may output sensing values corresponding to the sensingsignals provided from the sensing electrodes IE2-1 to IE2-4. In anembodiment, the first analog front-end AFE1_0 may be connected to thefirst sensing electrode IE2-1, and may output a first sensing valuecorresponding to sensing capacitance generated on the first sensingelectrode IE2-1, for example. Similarly, the second analog front-endAFE2_0 may be connected to the second sensing electrode IE2-2, and mayoutput a second sensing value corresponding to sensing capacitancegenerated on the second sensing electrode IE2-2.

Since the analog front-ends AFE1_0 to AFE4_0 are the same as each other,the analog front-ends AFEn_0 will be described as representative of theanalog front-ends AFE1_0 to AFE4_0.

In an embodiment, the analog front-end AFEn_0 may be implemented as asingle analog front-end, and may include at least one of a chargeamplifier CA (or first charge amplifier), a band pass filter BPF, amixer MX, a low pass filter LPF, and an analog-to-digital converter ADC.Since basic functions of the charge amplifier CA, the band pass filterBPF, the mixer MX, the low pass filter LPF, and the analog-to-digitalconverter ADC are similar to functions of the charge amplifier CA, theband pass filter BPF, the mixer MX, the low pass filter LPF, and theanalog-to-digital converter ADC described with reference to FIG. 6A,respectively, except for a differential function, duplicate descriptionswill be omitted.

The charge amplifier CA may receive the first sensing signalcorresponding to the sensing capacitance of the n-th sensing electrodeIE2-n through the n-th sensing line SL2-n, and may amplify the firstsensing signal to output amplified sensing signal CA_OUT.

The band pass filter BPF may select only a signal of a predeterminedfrequency band of the amplified sensing signal CA_OUT, and may outputthe filtered signal BPF_OUT.

The mixer MX may change the frequency of the filtered signal BPF_OUT tooutput the demodulated signal MX_OUT.

The low pass filter LPF may filter noise distributed in a high frequencyband of the demodulated signal MX_OUT, and may output an output signalLPF_OUT.

The analog-to-digital converter ADC may convert the analog-type outputsignal LPF_OUT into a digital-type sensing value and provide the sensingvalue to the signal processing unit DSP.

As described with reference to FIGS. 12 and 13 , the analog-to-digitalconverter ADC may be configured with a single analog front-end insteadof the fully differential analog front-end.

FIG. 14 is a drawing illustrating an input sensing device.

Referring to FIGS. 1 and 14 , the input sensing circuit IS-C_1 isdifferent from the input sensing circuit IS-C of FIG. 1 in that theinput sensing circuit IS-C_1 includes the analog front-ends AFE1_1 andAFE2_1. Since the input sensing device ISU_1 is substantially the sameas or similar to the input sensing device ISU of FIG. 1 except for theanalog front-ends AFE1_1 and AFE2_1, duplicate descriptions will beomitted.

Each of the analog front-ends AFE1_1 and AFE2_1 may be connected tothree sensing electrodes (or second signal lines) adjacent to each otheramong the sensing electrodes IE2-1 to IE2-4, may select two sensingelectrodes of the three sensing electrodes, and may output a sensingvalue corresponding to a difference between sensing capacitancescorresponding to the selected two sensing electrodes. In an embodiment,the first analog front-end AFE1_1 may be connected to the first sensingelectrode IE2-1, the second sensing electrode IE2-2, and the thirdsensing electrode IE2-3, may output a first sensing value correspondingto a difference between the sensing capacitance generated on the firstsensing electrode IE2-1 and the sensing capacitance generated on thesecond sensing electrode IE2-2 in the first section, and may output asecond sensing value corresponding to a difference between the sensingcapacitance generated on the second sensing electrode IE2-2 and thesensing capacitance generated on the third sensing electrode IE2-3 inthe second section (i.e., second section different from the firstsection), for example.

Similarly, the second analog front-end AFE2_1 may be connected to thethird sensing electrode IE2-3, the fourth sensing electrode IE2-4, andthe fifth sensing electrode (not shown), may output a third sensingvalue corresponding to a difference between the sensing capacitancegenerated on the third sensing electrode IE2-3 and the sensingcapacitance generated on the fourth sensing electrode IE2-4 in the firstsection, and may output a fourth sensing value corresponding to adifference between the sensing capacitance generated on the fourthsensing electrode IE2-4 and the sensing capacitance generated on thefifth sensing electrode (not shown).

That is, the analog front-ends AFE1_1 and AFE2_1 may be connected to thethree sensing electrodes, and may sequentially output the sensing valuesthrough time division driving. Compared with the input sensing deviceISU of FIG. 1 , the number of analog front-ends AFE1_1 and AFE2_1 maydecrease.

FIG. 15 is a block diagram illustrating an embodiment of an analog frontend included in the input sensing device of FIG. 14 .

Referring to FIGS. 14 and 15 , since the analog front-ends AFE1_1 andAFE2_1 are the same as each other, the analog front-end AFEn_1 will bedescribed as representative of the analog front-ends AFE1_1 and AFE2_1.

The analog front-end AFEn_1 is different from the analog front-end AFEnof FIG. 6A in that the analog front-end AFEn_1 further includes amultiplexer MUX. Since the analog front-end AFEn_1 is substantially thesame as or similar to the analog front-end AFEn of FIG. 6A except forthe multiplexer MUX, duplicate descriptions will be omitted.

The multiplexer MUX may receive the n-th sensing signal RXn providedthrough the n-th sensing signal line SL2-n, the n+1-th sensing signalRXn+1 provided through the n+l-th sensing signal line SL2-(n+1), and then+2-th sensing signal RXn+2 provided through the n+2-th sensing signalline SL2-(n+2), and may select and output two sensing signals among then-th sensing signal RXn, the n+1-th sensing signal RXn+1, and the n+2-thsensing signal RXn+2. Two sensing signals among the nth sensing signalRXn, the n+1-th sensing signal RXn+1, and the n+2-th sensing signalRXn+2 may be provided to the charge amplifier CA as input signals CA_IN1and CA_IN2. In an embodiment, the multiplexer MUX may be implemented asa multiplexer having an input/output ratio of 3:2, for example.

FIG. 16 illustrates the operation of the multiplexer MUX.

FIG. 16 is a drawing illustrating an operation of a multiplexer includedin the analog front end of FIG. 15 . FIG. 16 illustrates a firstmultiplexer MUX1 and a second multiplexer MUX2 respectively included inthe analog front-ends AFE1_1 and AFE2_1 shown in FIG. 14 .

In the first case CASE1 (or in the first section), a first selectionsignal SEL1 may be provided to the first multiplexer MUX1 and the secondmultiplexer MUX2. The first selection signal SEL1 may be provided fromthe external (e.g., signal processing unit DSP and driving signalgenerator TXD).

The first multiplexer MUX1 may connect the first sensing signal lineSL2-1 and the second sensing signal line SL2-2 to the first channel CH1and the second channel CH2, respectively, in response to the firstselection signal SELL Here, the first channel CH1 and the second channelCH2 may respectively correspond to or be connected to the inputterminals of the charge amplifier CA (refer to FIG. 15 ). Accordingly,the first sensing signal RX1 may be provided to the first channel CH1through the first sensing signal line SL2-1, and the second sensingsignal RX2 may be provided to the second channel CH2 through the secondsensing signal line SL2-2. In this case, the first analog front-endAFE1_1 (refer to FIG. 14 ) including the first multiplexer MUX1 mayoutput a first sensing value corresponding to the difference between thefirst sensing signal RX1 and the second sensing signal RX2.

Similarly, the second multiplexer MUX2 may connect the third sensingsignal line SL2-3 and the fourth sensing signal line SL2-4 to the thirdchannel CH3 and the four channel CH4 in response to the first selectionsignal SEL1, respectively. Here, the third channel CH3 and the fourthchannel CH4 may respectively correspond to or be connected to the inputterminals of the charge amplifier CA (refer to FIG. 15 ). Accordingly,the third sensing signal RX3 may be provided to the third channel CH3through the third sensing signal line SL2-3, and the fourth sensingsignal RX4 may be provided to the fourth channel CH4 through the fourthsensing signal line SL2-4. In this case, the second analog front-endAFE2_1 (refer to FIG. 14 ) including the second multiplexer MUX2 mayoutput a third sensing value corresponding to the difference between thethird sensing signal RX3 and the fourth sensing signal RX4.

That is, in the first case CASE1 (or in the first section), the analogfront-ends AFE1_1 and AFE2_1 may output odd-numbered sensing values.

In the second case CASE2 (or in the second section), the secondselection signal SEL2 may be provided to the first multiplexer MUX1 andthe second multiplexer MUX2.

The first multiplexer MUX1 may connect the second sensing signal lineSL2-2 and the third sensing signal line SL2-3 to the first channel CH1and the second channel CH2, respectively, in response to the secondselection signal SEL2. Accordingly, the second sensing signal RX2 may beprovided to the first channel CH1 through the second sensing signal lineSL2-2, and the third sensing signal RX3 may be provided to the secondchannel CH2 through the third sensing signal line SL2-3. In this case,the first analog front-end AFE1_1 including the first multiplexer MUX1may output a second sensing value corresponding to the differencebetween the second sensing signal RX2 and the third sensing signal RX3.

Similarly, the second multiplexer MUX2 may connect the fourth sensingsignal line SL2-4 and the fifth sensing signal line SL2-5 to the thirdchannel CH3 and the third channel CH4, respectively, in response to thesecond selection signal SEL2. Accordingly, the fourth sensing signal RX4may be provided to the third channel CH3 through the fourth sensingsignal line SL2-4, and the fifth sensing signal RX5 may be provided tothe fourth channel CH4 through the fifth sensing signal line SL2-5. Inthis case, the second analog front-end AFE2_1 including the secondmultiplexer MUX2 may output a fourth sensing value corresponding to adifference between the fourth sensing signal RX4 and the fifth sensingsignal RX5.

That is, in the second case CASE2 (or in the second section), the analogfront-ends AFE1_1 and AFE2_1 may output even-numbered sensing values.

As described with reference to FIGS. 15 and 16 , the analog front-endAFEn_1 may include a multiplexer MUX having an input/output ratio of3:2, and may output sensing values through time division driving.Accordingly, the number of the analog front-ends AFE1_1 and AFE2_1 inthe input sensing circuit IS-C_1 (refer to FIG. 14 ) may decrease, andthe input sensing circuit IS-C_1 may be more easily integrated.

FIG. 17A is a block diagram illustrating another embodiment of an analogfront end included in the input sensing circuit of FIG. 14 .

Referring to FIGS. 14, 15, and 17A, the analog front-end AFEn_2 isdifferent from the analog front-end AFEn_1 of FIG. 15 in that it furtherincludes a negative capacitor C_N. Since the analog front-end AFEn_2 issubstantially the same as or similar to the analog front-end AFEn_1 ofFIG. 15 except for the negative capacitor C_N, duplicate descriptionswill be omitted.

The negative capacitor C_N (or negative capacitor circuit, or parasiticcapacitance compensation circuit) may be connected to each of the inputterminals of the multiplexer MUX, or may be provided on each of thesensing signal lines.

In an embodiment, the negative capacitor C_N may be connected to thefirst input terminal of the multiplexer MUX or the n-th sensing signalline SL2-n, for example. In addition, the negative capacitor C_N may beconnected to each of the second input terminal (or n+1-th sensing signalline SL2-(n+1)) of the multiplexer MUX and the third input terminal (orn+2-th sensing signal lines SL2-(n+2)) of the multiplexer MUX.

For reference, as will be described later with reference to FIG. 22 , asa thickness of a thin film encapsulation layer in the display paneldecreases, a distance between the driving electrode and sensingelectrode in the input sensing device ISU and a light emitting elementand a common electrode in the display panel may be narrowed, and theparasitic capacitance generated therebetween may increase. In addition,as an area of the display device becomes larger, an overlapping areabetween the driving and sensing electrodes in the input sensing deviceISU and the common electrode of the light emitting device may increase,and the parasitic capacitance may increase. The parasitic capacitancemay cause a delay in response to the touch driving signal and thesensing signal, and may reduce touch sensing sensitivity.

The negative capacitor C_N may be implemented as a negative capacitorfield effect transistor (“FET”), and may be discharged when a voltage ofa line corresponding thereto increases and be charged when a voltage ofa line corresponding thereto decreases. Therefore, the negativecapacitor C_N may offset the parasitic capacitance.

As described with reference to FIG. 17A, the analog front-end AFEn_2 mayreduce parasitic capacitance for sensing electrodes in the input sensingdevice ISU by the negative capacitor C_N. Accordingly, touch sensingsensitivity may be improved.

In FIG. 17A, the analog front-end AFEn_2 is illustrated as including themultiplexer MUX, but is not limited thereto. FIG. 17B is a block diagramillustrating another embodiment of an analog front end included in theinput sensing circuit IS-C of FIG. 1 . As shown in FIG. 17B, thenegative capacitor C_N may be applied to the analog front-end AFEndescribed with reference to FIG. 6A. In addition, the negative capacitorC_N may be applied to the analog front-end AFEn described with referenceto FIG. 6B and the analog front-end AFEn_0 described with reference toFIG. 13 .

FIG. 18 is a perspective view illustrating an embodiment of a displaydevice.

Referring to FIG. 18 , the display device DD may be provided in variousshapes, and for example, may be provided in a quadrangular (e.g.,rectangular) plate shape having two pairs of sides parallel to eachother. When the display device DD is provided in a plate of aquadrangular (e.g., rectangular) shape, one pair of sides of the twopairs of sides may be provided longer than the other pair of sides.

The display device DD may display an image through a display surface.The display surface may be parallel to a surface defined by a firstdirection axis corresponding to the first direction DR1 and a seconddirection axis corresponding to the second direction DR2. A normaldirection of the display surface, that is, a thickness direction of thedisplay device DD, is defined as the third direction DR3.

A front surface (or upper surface) and a rear surface (or lower surface)of each member, layer, or unit described below may be divided along thethird direction DR3. However, the first, second, and third directionsDR1, DR2, and DR3 may be only examples, may be relative concepts, andmay be changed to different directions.

The display device DD may have a flat display surface. However, thedisplay surface is not limited thereto, and for example, the displaydevice DD may include various types of display surfaces capable ofdisplaying an image, such as a curved display surface or athree-dimensional (“3D”) display surface. When the display device DD hasthe 3D display surface, the 3D display surface may, for example, includea plurality of display areas facing different directions. The 3D displaysurface may be implemented as a polygonal columnar display surface.

The display device DD may be a flexible display device. In anembodiment, the display device DD may be applied to a foldable displaydevice, a bendable display device, a rollerable display device, and thelike, for example. The invention is not limited thereto, but may be arigid display device.

The display device DD may be not only applied to a large electronicdevice such as a television, a monitor, and an electric signboard, butalso a small electronic device such as a mobile phone, a tablet, anavigation device, a game device, and a smart watch. In addition, thedisplay device DD may be applied to a wearable electronic device such asa head-mount display.

The display device DD may include a display panel DP and an inputsensing panel ISP (or input sensing device ISU (refer to FIG. 1 ), inputsensing layer).

The display panel DP and the input sensing panel ISP may be provided bya continuous process. However, the display panel DP and the inputsensing panel ISP are not limited thereto, and for example, the displaypanel DP and the input sensing panel ISP may be coupled to each otherthrough an adhesive member. The adhesive member may include aconventional adhesive or pressure-sensitive adhesive. In an embodiment,the adhesive member may be an optically transparent adhesive member, forexample.

Configurations formed through a continuous process with otherconfigurations are represented as “layers”, and configurations coupledwith other configurations through an adhesive member are represented as“panel”. The panel may include a base layer providing a base surface,for example a synthetic resin film, a composite material film, a glasssubstrate, etc., but “layer” may not include the base layer. In otherwords, the input sensing panel ISP represented as a “layer” may bedisposed on a base surface provided by the display panel DP.

The input sensing panel ISP may sense a contact on or input to thedisplay surface of the display device DD by an external medium such as ahand or a pen.

The display panel DP may be a display panel of an emission type. In anembodiment, the display panel DP may be an organic light emittingdisplay panel or a quantum dot light emitting display panel, forexample.

In an embodiment, the display device DD may further include ananti-reflective panel and a window panel.

The anti-reflective panel may be disposed on the input sensing panelISP, and may reduce reflectance of external light incident on thedisplay surface of the display device DD from the outside. In anembodiment, the anti-reflective panel may include color filters, forexample. The color filters may have a predetermined arrangement. Thearrangement of color filters may be determined considering the lightemitting colors of the pixels included in the display panel DP.

The window panel may be disposed on the input sensing panel ISP, and mayprotect the display panel DP and the input sensing panel ISP from theexternal (e.g., external impact). The window panel may include asynthetic resin film and/or a glass substrate. The window panel mayinclude two or more films coupled by an adhesive member.

FIG. 19 is a plan view illustrating an embodiment of a display panelincluded in the display device of FIG. 18 .

Referring to FIGS. 18 and 19 , the display panel DP may include adisplay area DP-DA in which an image is displayed and a non-display areaDP-NDA adjacent to the display area DP-DA. The non-display area DP-NDAis an area in which an image is not displayed. The non-display areaDP-NDA may be disposed outside the display area DP-DA.

The display area DP-DA may include pixel areas in which pixels PX areprovided. A pad area NDA-PD in which pads of lines are provided may beprovided in the non-display area DP-NDA. A data driver (not shown) forproviding data signals to the pixels PX may be provided in thenon-display area DP-NDA. The data driver may provide a data signal toeach of the pixels PX through data lines. The data driver may beincluded in a timing control circuit TC, which will be described later.

The display panel DP may include a driving circuit GDC, signal linesSGL, signal pads DP-PD, and pixels PX.

The pixels PX may be disposed in the display area DP-DA. Each of thepixels PX may include a light emitting element and a pixel drivingcircuit connected to the light emitting element. In an embodiment, thelight emitting element may include an organic light emitting diode, oran inorganic light emitting diode such as a micro light emitting diode(“LED”), or a quantum dot light emitting diode. In addition, the lightemitting element may be a light emitting element including an organicmaterial and an inorganic material in combination, for example. Further,each of the pixels PX may include a single light emitting element, or inanother embodiment, each of the pixels PX may include a plurality oflight emitting elements, and the plurality of light emitting elementsmay be connected to each other in series, parallel, or in series andparallel.

The driving circuit GDC may include a scan driving circuit. The scandriving circuit may generate scan signals, and may sequentially provideor output the scan signals to the scan lines GL. The scan drivingcircuit may further provide another control signal to the drivingcircuit of the pixels PX.

In an embodiment, the scan driving circuit may include thin filmtransistors provided through the same process as the driving circuit ofthe pixels PX, for example, a low temperature polycrystalline silicon(“LTPS”) process or a low temperature polycrystalline oxide (“LTPO”)process.

The signal lines SGL may include scan lines GL, data lines DL, powerlines PL, and control signal lines CSL. Each of the scan lines GL may beconnected to a corresponding one of the pixels PX, and each of the datalines DL may be connected to a corresponding one of the pixels PX. Thepower line PL may be connected to the pixels PX. The control signal lineCSL may provide control signals to the scan driving circuit.

The signal lines SGL may overlap the display area DP-DA and thenon-display area DP-NDA. The signal lines SGL may include a pad unit (orpad portion) and a line unit (or line portion). The line unit mayoverlap the display area DP-DA and the non-display area DP-NDA. The padunit may be connected to an end of the line unit. The pad unit may bedisposed in the non-display area DP-NDA, and may overlap a correspondingsignal pad among the signal pads DP-PD. An area in which the signal padsDP-PD are disposed among the non-display area DP-NDA may be defined asthe pad area NDA-PD.

The line unit connected to the pixels PX may constitute most of thesignal lines SGL. The line unit may be connected to transistors of thepixels PX. The line unit may have a single layer/multilayer structure,and the line unit may be a single body or include two or more portions.The two or more portions may be disposed on different layers, and may beconnected to each other through a contact hole passing through theinsulating layer disposed between the two or more portions.

The display panel DP may further include dummy pads IS-DPD disposed inthe pad area NDA-PD. Since the dummy pads IS-DPD are provided throughthe same process as the signal lines SGL, they may be disposed in thesame layer as the signal lines SGL. The dummy pads IS-DPD may beselectively provided in the display device DD including an input sensinglayer, and may be omitted in the display device DD including an inputsensing panel.

FIG. 19 further illustrates a circuit board PCB electrically connectedto the display panel DP. The circuit board PCB may be a flexible circuitboard or a rigid circuit board. The circuit board PCB may be directlycoupled to the display panel DP or may be connected to the display panelDP through another circuit board.

A timing control circuit TC for controlling an operation of the displaypanel DP may be disposed on the circuit board PCB. The timing controlcircuit TC may receive input image data and timing signals (e.g.,vertical synchronization signal, horizontal synchronization signal,clock signals) from the external (e.g., host system such as anapplication processor), may generate a gate driving control signal forcontrolling the driving circuit GDC based on the timing signals, and mayprovide a gate driving control signal to the driving circuit GDC. Here,the vertical synchronization signal among the timing signals may definea start of one display section (or one frame) in which an image (orframe image) of one frame is displayed, or a start (or transmissionstart) of image data corresponding to one frame, and the horizontalsynchronization signal among the timing signals may define a section inwhich each of horizontal line images included in an image of one frameis output (e.g., an image is output through pixels included in the samerow). In addition, the timing control circuit TC may generate a datadriving control signal for controlling the data driver, may provide thedata driving control signal to the data driver, and may rearrange inputimage data to provide the data driver.

In addition, an input sensing circuit IS-C (refer to FIG. 1 ) may bedisposed on the circuit board PCB.

Each of the timing control circuit TC and the input sensing circuit IS-Cmay be disposed (e.g., mounted) on the circuit board PCB in the form ofan integrated chip. In another embodiment, the timing control circuit TCand the input sensing circuit IS-C may be disposed (e.g., mounted) onthe circuit board PCB in the form of one integrated chip, for example.The circuit board PCB may include circuit board pads PCB-P electricallyconnected to the display panel DP. Although not shown, the circuit boardPCB may further include signal lines connecting the circuit board padsPCB-P to the timing control circuit TC and/or the input sensing circuitIS-C.

FIG. 20 is a plan view illustrating an embodiment of an input sensingpanel included in the display device of FIG. 18 . FIG. 21 is an enlargedplan view of a partial area FF of the input sensing panel of FIG. 20 .

Referring to FIGS. 19 and 20 , the input sensing panel ISP may include asensing area SA that senses a user's input, for example, a touch and/ora pressure when touching, and a peripheral area PA provided in at leastone side of the sensing area SA.

The sensing area SA may correspond to the display area DP-DA of thedisplay panel DP, and may have substantially the same area as or alarger area than the display area DP-DA. The peripheral area PA may bedisposed adjacent to the sensing area SA. In addition, the peripheralarea PA may correspond to the non-display area DP-NDA of the displaypanel DP.

As described with reference to FIG. 1 , the input sensing panel ISP mayinclude driving electrodes IE1-1 to IE1-5 and sensing electrodes IE2-1to IE2-4 provided in the sensing area SA, and driving signal lines SL1-1to SL1-5 and sensing signal lines SL2-1 to SL2-4 provided in theperipheral area PA.

The first sensor units SP1 may be arranged along the second directionDR2 in one driving electrode, and the second sensor units SP2 may bearranged along the first direction DR1 in one sensing electrode. Each ofthe first connection units CP1 may connect first sensor units SP1adjacent to each other, and each of the second connection units CP2 mayconnect second sensor units SP2 adjacent to each other.

The driving electrodes IE1-1 to IE1-5 and the sensing electrodes IE2-1to IE2-4 may have a mesh pattern or a mesh structure. As shown in FIG.21 , the mesh pattern may include mesh lines, which are metal linesforming at least one mesh hole IS-OPR, IS-OPG, and IS-OPB (or opening).The mesh holes IS-OPR, IS-OPG, and IS-OPB defined by the mesh lines mayhave a rhombus planar shape, but are not limited thereto.

Since the driving electrodes IE1-1 to IE1-5 and the sensing electrodesIE2-1 to IE2-4 have a mesh pattern, parasitic capacitance with theelectrodes of the display panel DP may decrease.

In addition, as shown in FIG. 21 , in a partial area FF, the drivingelectrodes IE1-1 to IE1-5 and the sensing electrodes IE2-1 to IE2-4 maynot overlap emission area PXA-R, PXA-G, and PXA-B. Here, each of theemission areas PXA-R, PXA-G, and PXA-B may be included in the pixels PX(or pixel areas in which the pixels PX are provided) described withreference to FIG. 19 . Accordingly, the driving electrodes IE1-1 toIE1-5 and the sensing electrodes IE2-1 to IE2-4 may not be visuallyrecognized by the user of the display device DD.

In an embodiment, the driving electrodes IE1-1 to IE1-5 and the sensingelectrodes IE2-1 to IE2-4 may include aluminum, copper, chromium,nickel, titanium, or the like, for example. However, the invention isnot limited thereto, and the driving and sensing electrodes may includevarious metals.

When the driving electrodes IE1-1 to IE1-5 and the sensing electrodesIE2-1 to IE2-4 are, for example, including a metal capable of performinga low-temperature process, damage to the light emitting element may beprevented even when the input sensing panel ISP is provided bycontinuous process after manufacturing process of the display panel DP.

When the driving electrodes IE1-1 to IE1-5 and the sensing electrodesIE2-1 to IE2-4 are directly disposed on the display panel DP in a meshpattern, flexibility of the display device DD may be improved.

In FIG. 20 , the driving electrodes IE1-1 to IE1-5 and the sensingelectrodes IE2-1 to IE2-4 are shown to include the first sensor unitsSP1 and the second sensor units SP2 having a rhombus shape, but theinvention is not limited thereto, and the first sensor units SP1 and thesecond sensor units SP2 may have a polygonal shape. The drivingelectrodes IE1-1 to IE1-5 and the sensing electrodes IE2-1 to IE2-4 mayhave a shape (e.g., bar shape) in which there is no distinction betweenthe sensor unit and the connection unit.

As described with reference to FIG. 1 , the driving signal lines SL1-1to SL1-5 may be connected to one end of the driving electrodes IE1-1 toIE1-5, respectively. The sensing signal lines SL2-1 to SL2-4 may beconnected to both ends of the sensing electrodes IE2-1 to IE2-4.

Since the sensing electrodes IE2-1 to IE2-4 are longer than the drivingelectrodes IE1-1 to IE1-5, a voltage drop of a detection signal (ortransmission signal) may be greater, and thus sensing sensitivity maydecrease. Since the detection signal (or transmission signal) istransmitted through the sensing signal lines SL2-1 to SL2-4 connected toboth ends of the sensing electrodes IE2-1 to IE2-4, the voltage drop ofthe detection signal (or transmission signal) and a decrease in sensingsensitivity may be prevented.

The driving signal lines SL1-1 to SL1-5 and the sensing signal linesSL2-1 to SL2-4 may include a line unit SL-L and a pad unit SL-P. The padportions SL-P may be arranged to the pad area NDA-PD. The pad unit SL-Pmay overlap dummy pads IS-DPD illustrated in FIG. 19 .

The input sensing panel ISP may include signal pads DP-PD. The signalpads DP-PD may be arranged in the pad area NDA-PD.

Referring to FIG. 21 , the first sensor units SP1 may not overlap theemission areas PXA-R, PXA-G, and PXA-B, and may overlap the non-emissionarea NPXA.

The mesh lines (e.g., metal lines) of the first sensor units SP1 maydefine the mesh holes IS-OPR, IS-OPG, and IS-OPB. The mesh holes IS-OPR,IS-OPG, and IS-OPB may correspond one-to-one to the emission areasPXA-R, PXA-G, and PXA-B. The emission areas PXA-R, PXA-G, and PXA-B maybe exposed by mesh holes IS-OPR, IS-OPG, and IS-OPB.

A line width of the mesh lines may be smaller than a width of a pixeldefinition layer corresponding to the non-emission area NPXA (i.e.,pixel definition layer defining the emission areas PXA-R, PXA-G, andPXA-B).

Accordingly, it is possible to minimize blocking of light emitted fromthe emission areas PXA-R, PXA-G, and PXA-B by the mesh lines, and toprevent the mesh lines from being visually recognized by the user.

The mesh lines may have a three-layer structure oftitanium/aluminum/titanium.

The emission areas PXA-R, PXA-G, and PXA-B may be divided into aplurality of groups based on the color of light generated by the lightemitting element. In FIG. 21 , the emission areas PXA-R, PXA-G, andPXA-B divided into three groups based on emission color are illustrated.

The emission areas PXA-R, PXA-G, and PXA-B may have different areasdepending on the color emitted from the light emitting element. Theareas of the emission areas PXA-R, PXA-G, and PXA-B may be determineddepending on a type of the light emitting element.

The mesh holes IS-OPR, IS-OPG, and IS-OPB may be divided into aplurality of groups having different areas. The mesh holes IS-OPR,IS-OPG, and IS-OPB may be divided into three groups depending on theemission areas PXA-R, PXA-G, and PXA-B corresponding thereto.

In FIG. 21 , the mesh holes IS-OPR, IS-OPG, and IS-OPB are shown tocorrespond one-to-one to the emission areas PXA-R, PXA-G, and PXA-B, butare not limited thereto. In an embodiment, each of the mesh holesIS-OPR, IS-OPG, and IS-OPB may correspond to two or more emission areasPXA-R, PXA-G, and PXA-B, for example.

In FIG. 21 , the areas of the emission areas PXA-R, PXA-G, and PXA-B areshown to be various, but are not limited thereto. In an embodiment, thesize of the emission areas PXA-R, PXA-G, and PXA-B may be the same aseach other, and also the size of the mesh holes IS-OPR, IS-OPG, andIS-OPB may be the same as each other, for example. The planar shape ofthe mesh holes IS-OPR, IS-OPG, and IS-OPB is not limited thereto, andmay have a polygonal shape different from a rhombus. The planar shape ofthe mesh holes IS-OPR, IS-OPG, and IS-OPB may have a polygonal shapewith rounded corners.

FIG. 22 is a cross-sectional view illustrating an embodiment of adisplay device taken along line I-I′ of FIG. 21 .

Referring to FIG. 22 , the display device may include a base layer BL(or substrate), a buffer layer BFL, a pixel circuit layer PCL, a lightemitting element layer LDL, a thin film encapsulation layer TFE, and aninput sensing panel ISP.

The base layer BL may include a synthetic resin film. The syntheticresin layer may be a polyimide-based resin layer, and the materialthereof is not particularly limited. In addition, the base layer BL mayinclude a glass substrate, a metal substrate, an organic/inorganiccomposite material substrate, or the like.

The buffer layer BFL may be provided on the base layer BL. The bufferlayer BFL may prevent diffusion of impurities into the transistor Tprovided on the base layer BL, and may improve flatness of the baselayer BL. The buffer layer BFL may be provided as a single layer, butmay also be provided as multiple layers of at least two or more layers.The buffer layer BFL may be an inorganic insulating film including aninorganic material. In an embodiment, the buffer layer BFL may includesilicon nitride, silicon oxide, silicon oxynitride, or the like, forexample. When the buffer layer BFL is provided as multiple layers, eachlayer may include the same material or may include different materials.The buffer layer BFL may be omitted in some cases.

The pixel circuit layer PCL may include at least one insulating layerand a circuit element. The insulating layer may include at least oneinorganic layer and at least one organic layer. The circuit element mayinclude signal lines, pixel driving circuits, and the like.

The semiconductor pattern ODP of the transistor T may be disposed on thebuffer layer BFL. In an embodiment, the semiconductor pattern ODP mayinclude at least one of amorphous silicon, polysilicon, and metal oxidesemiconductor.

The first insulating layer INS1 may be disposed on the semiconductorpattern ODP. The first insulating layer INS1 may be an inorganicinsulating layer including an inorganic material. In an embodiment, thefirst insulating layer INS1 may include at least one of silicon nitride,silicon oxide, silicon oxynitride, and the like, for example.

A control electrode GE of the transistor T may be disposed on the firstinsulating layer INS1. The control electrode GE may be manufacturedaccording to the same photolithography process as the scan lines GL(refer to FIG. 19 ).

A second insulating layer INS2 covering the control electrode GE may bedisposed on the first insulating layer INS1. The second insulating layerINS2 may be an inorganic insulating layer including an inorganicmaterial. In an embodiment, the second insulating layer INS2 may includeat least one of silicon nitride, silicon oxide, silicon oxynitride, andthe like, for example.

A first transistor electrode DE (or drain electrode) and a secondtransistor electrode SE (or source electrode) of the transistor T may bedisposed on the second insulating layer INS2.

The first transistor electrode DE and the second transistor electrode SEmay be respectively connected to the semiconductor pattern ODP through afirst through hole CH1 and a second through hole CH2 passing through thefirst insulating layer INS1 and the second insulating layer INS2. Inanother embodiment of the invention, the transistor T may be implementedas a bottom gate structure.

A third insulating layer INS3 covering the first transistor electrode DEand the second transistor electrode SE may be disposed on the secondinsulating layer INS2. The third insulating layer INS3 may provide aflat surface. In an embodiment, the third insulating layer INS3 mayinclude an organic layer such as acrylic resin, epoxy resin, phenolicresin, polyamide resin, polyimide resin, etc.

The light emitting element layer LDL may be disposed on the thirdinsulating layer INS3. The light emitting element layer LDL may includea pixel definition layer PDL and a light emitting element OLED.

The pixel definition layer PDL may include an organic material. Thefirst electrode AE may be disposed on the third insulating layer INS3.The first electrode AE may be connected to the second transistorelectrode SE through a third through hole CH3 passing through the thirdinsulating layer INS3. An opening OP may be defined in the pixeldefinition layer PDL, and the opening OP may define emission areasPXA-R, PXA-G, and PXA-B. The opening OP of the pixel definition layerPDL may expose at least a portion of the first electrode AE. In amodified embodiment, the pixel definition layer PDL may be omitted.

The pixel PX (refer to FIG. 19 ) may be disposed in the display areaDP-DA. The display area DP-DA may include an emission area PXA and anon-emission area NPXA adjacent to the emission area PXA. Thenon-emission area NPXA may surround the emission area PXA. The emissionarea PXA may be defined to correspond to a portion area of the firstelectrode AE exposed by the opening OP. The non-emission area NPXA maybe defined to correspond to the pixel definition layer PDL.

The light emitting element OLED may include a first electrode AEconnected to the second transistor electrode SE, an emission layer EMLdisposed on the first electrode AE, and a second electrode CE disposedon the light emitting layer EML. In an embodiment, the light emittingelement OLED may be an organic light emitting diode, for example.

One of the first electrode AE and the second electrode CE may be ananode electrode, and the other thereof may be a cathode electrode. In anembodiment, the first electrode AE may be an anode electrode, and thesecond electrode CE may be a cathode electrode, for example.

At least one of the first electrode AE and the second electrode CE maybe a transmissive electrode. In an embodiment, when the light emittingelement OLED is an organic light-emitting element of a bottom-emissiontype, the first electrode AE may be a transmissive electrode, and thesecond electrode CE may be a reflective electrode, for example. When thelight emitting element OLED is an organic light emitting element of atop emission type, the first electrode AE may be a reflective electrode,and the second electrode CE may be a transmissive electrode. When thelight emitting element OLED is an organic light-emitting element of adouble-sided emission type, both the first electrode AE and the secondelectrode CE may be transmissive electrodes. In the embodiment, a casewhere the light emitting element OLED is an organic light emittingelement of a top emission type and the first electrode AE is an anodeelectrode will be described as an example.

In each pixel area, the first electrode AE may be disposed on the thirdinsulating layer INS3. The first electrode AE may include a reflectivelayer capable of reflecting light and a transparent conductive layerdisposed on or under the reflective layer. At least one of thetransparent conductive layer and the reflective layer may be connectedto the second transistor electrode SE.

The reflective layer may include a material capable of reflecting light.In an embodiment, the reflective layer may include at least one ofaluminum (Al), silver (Ag), chromium (Cr), molybdenum (Mo), platinum(Pt), nickel (Ni), and any alloys thereof, for example.

The transparent conductive layer may include a transparent conductiveoxide. In an embodiment, the transparent conductive layer may include atleast one transparent conductive oxide including at least one of indiumtin oxide (“ITO”), indium zinc oxide (“IZO”), aluminum zinc oxide(“AZO”), gallium doped zinc oxide (“GZO”), zinc tin oxide (“ZTO”),gallium tin oxide (“GTO”), and fluorine doped tin oxide (“FTO”), forexample.

The emission layer EML may be disposed on the exposed surface of thefirst electrode AE. The emission layer EML may have a multilayered thinfilm structure at least including a light generation layer (“LGL”). Inan embodiment, the emission layer EML may include a hole injection layerfor injecting holes, a hole transport layer having excellent holetransportability and for increasing a chance of recombination of holesand electrons by blocking a movement of electrons which are not coupledin a light generating layer, the light generating layer which emitslight by recombination of injected electrons and holes, a hole blockinglayer for blocking a movement of holes which are not coupled in thelight generating layer, an electron transport layer for smoothlytransporting electrons to the light generating layer, and an electroninjection layer for injecting electrons, for example.

In an embodiment, the color of light generated in the light generatinglayer may be one of red, green, blue, and white, for example, but is notlimited thereto. In an embodiment, the color of light generated in thelight generating layer of the emission layer EML may be one of magenta,cyan, and yellow, for example.

The hole injection layer, the hole transport layer, the hole blockinglayer, the electron transport layer, and the electron injection layermay be common layers connected to each other in adjacent pixel areas.

The second electrode CE may be disposed on the emission layer EML. Thesecond electrode CE may be a transflective layer. In an embodiment, thesecond electrode CE may be a thin metal layer having a thicknesssufficient to transmit light, for example. The second electrode CE maytransmit some of the light generated in the light generating layer, andmay reflect the rest of the light generated in the light generatinglayer.

The second electrode CE may include a material having a lower workfunction than the transparent conductive layer. In an embodiment, thesecond electrode CE may include at least one of molybdenum (Mo),tungsten (W), silver (Ag), magnesium (Mg), aluminum (Al), platinum (Pt),palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir),chromium (Cr), lithium (Li), calcium (Ca), and an alloy thereof, forexample.

Some of the light emitted from the emission layer EML may not transmitthe second electrode CE, and the light reflected from the secondelectrode CE may be reflected again by the reflective layer (not shown).That is, between the reflective layer and the second electrode CE, lightemitted from the emission layer EML may resonate. Light extractionefficiency of the light emitting element OLED may be improved by theresonance of light.

A distance between the reflective layer and the second electrode CE maybe different depending on the color of light generated by the lightgenerating layer. That is, the distance between the reflective layer andthe second electrode CE may be adjusted to match a resonance distancedepending on the color of light generated in the light generating layer.

The thin film encapsulation layer TFE may be disposed on the secondelectrode CE. The thin film encapsulation layer TFE may be commonlydisposed on the pixels PX. The thin film encapsulation layer TFE maydirectly cover the second electrode CE. In an embodiment, a cappinglayer covering the second electrode CE may be further disposed betweenthe thin film encapsulation layer TFE and the second electrode CE. Inthis case, the thin film encapsulation layer TFE may directly cover thecapping layer.

The thin film encapsulation layer TFE may include a first encapsulationinorganic layer IOL1, an encapsulation organic layer OL, and a secondencapsulation inorganic layer IOL2 sequentially stacked on the secondelectrode CE. In an embodiment, the first and second encapsulationinorganic layers IOL1 and IOL2 may include an inorganic insulatingmaterial such as polysiloxane, silicon nitride, silicon oxide, siliconoxynitride, and the like. In an embodiment, the encapsulation organiclayer OL may include an organic insulating material such as apolyacrylic compound, a polyimide compound, a fluorine-based carboncompound such as Teflon, a benzocyclobutene compound, and the like.

A thickness T1 of the thin film encapsulation layer TFE (orencapsulation organic layer OL) may be adjusted so that noise generatedby components of the light emitting element layer LDL does not affectthe input sensing panel ISP. However, as the display device becomesthinner, the thickness T1 of the thin film encapsulation layer TFEdecreases (e.g., thickness T1 is 10 μm or less), and the noise generatedby the components of the light emitting element layer LDL may affect theinput sensing panel ISP.

The input sensing panel ISP may be provided on the thin filmencapsulation layer TFE. The input sensing panel ISP may include a firstconductive layer IS-CL1, a fourth insulating layer IS-IL1, a secondconductive layer IS-CL2, and a fifth insulating layer IS-IL2. Each ofthe first conductive layer IS-CL1 and the second conductive layer IS-CL2may have a single layer structure or a multilayer structure.

A conductive layer having the single layer structure may include a metallayer or a transparent conductive layer. In an embodiment, the metallayer may include at least one of molybdenum, silver, titanium, copper,aluminum, and alloys thereof. In an embodiment, the transparentconductive layer may include a transparent conductive oxide such as ITO,IZO, zinc oxide (ZnO), indium tin zinc oxide (“ITZO”), and the like. Inan embodiment, the transparent conductive layer may include conductivepolymers such as poly(3,4-ethylenedioxythiophene) (“PEDOT”), metal nanowire, grapheme, or the like.

The conductive layer having multilayer structure may includemultilayered metal layers. In an embodiment, the multilayered metallayers may have a three-layer structure, for exampletitanium/aluminum/titanium. The conductive layer having multilayerstructure may include at least one metal layer and at least onetransparent conductive layer.

Each of the first conductive layer IS-CL1 and the second conductivelayer IS-CL2 may include a plurality of patterns. Hereinafter, the firstconductive layer IS-CL1 may include first conductive patterns, and thesecond conductive layer IS-CL2 may include second conductive patterns.Each of the first and second conductive patterns may include driving andsensing electrodes and driving and sensing signal lines described withreference to FIG. 20 .

Each of the fourth insulating layer IS-IL1 and the fifth insulatinglayer IS-IL2 may have a single layer or multilayer structure. Each ofthe fourth insulating layer IS-IL1 and the fifth insulating layer IS-IL2may include an inorganic material, an organic material, or a compositematerial.

At least one of the fourth insulating layer IS-IL1 and the fifthinsulating layer IS-IL2 may include an inorganic layer. In anembodiment, the inorganic layer may include at least one of aluminumoxide, titanium oxide, silicon oxide silicon oxynitride, zirconiumoxide, and hafnium oxide, for example.

At least one of the fourth insulating layer IS-IL1 and the fifthinsulating layer IS-IL2 may include an organic layer. In an embodiment,the organic layer may include at least one of acryl-based resin,methacryl-based resin, polyisoprene, vinyl-based resin, epoxy-basedresin, urethane-based resin, cellulose-based resin, siloxane-basedresin, polyimide-based resin, polyamide-based resin, and perylene-basedresin, for example.

Referring to FIGS. 20 to 22 , a first sensor unit SP1 of the drivingelectrodes IE1-1 to IE1-5 may include a two-layered mesh-shaped metallayer including a first mesh pattern SP1-1 and a second mesh patternSP1-2. That is, the second mesh pattern SP1-2 may be disposed on thefirst mesh pattern SP1-1, and the fourth insulating layer IS-IL1 may beprovided between the second mesh pattern SP1-2 and the first meshpattern SP1-1. A connection contact hole CNT-D may be defined in thefourth insulating layer IS-IL1, and a contact unit SP1-0 may be disposedin the connection contact hole CNT-D to electrically connect the firstmesh pattern SP1-1 and the second mesh pattern SP1-2. The contact unitSP1-0 may include a conductive material. In an embodiment, the contactunit SP1-D may include the same material as that of the first meshpattern SP1-1 or the second mesh pattern SP1-2 for convenience ofprocessing, for example. In another embodiment, the contact unit SP1-Dmay include a material having higher electrical conductivity than thefirst mesh pattern SP1-1 or the second mesh pattern SP1-2, for example.

A fifth insulating layer IS-IL2 may be disposed on the second meshpattern SP1-2. The fifth insulating layer IS-IL2 may cover all of thesecond mesh pattern SP1-2, and may function as a planarization layer.

The second sensor unit SP2 of the sensing electrodes IE2-1 to IE2-4 mayalso include a two-layered mesh pattern similar to the first sensor unitSP1 of the driving electrodes IE1-1 to IE1-4. The two-layered meshpattern may be disposed with the fourth insulating layer IS-IL1interposed therebetween, and may be electrically connected by thecontact unit through the connection contact hole CNT-D defined in thefourth insulating layer IS-IL1.

The invention is not limited thereto, and the driving and sensingelectrodes may include a single layer of mesh pattern as anotherexample.

While the invention has been shown and described with reference topredetermined embodiments thereof, it will be understood by thoseskilled in the art that various changes in forms and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims and their equivalents. Accordingly, thetechnical scope of the invention may be determined by on the technicalscope of the accompanying claims.

What is claimed is:
 1. An input sensing device comprising: an inputsensing panel which includes electrodes; a driving signal generatorwhich provides driving signals to the electrodes; and a sensing unitwhich receives sensing signals according to the driving signals from theelectrodes, wherein the driving signals include a first driving signaland a second driving signal which have different frequencies, andwherein the sensing unit samples a first sensing signal according to thefirst driving signal and a second sensing signal according to the seconddriving signal at a same frequency.
 2. The input sensing device of claim1, wherein each of the driving signals includes a sinusoidal wave. 3.The input sensing device of claim 1, wherein the input sensing panelincludes a first area and a second area, wherein the first area isfarther from the driving signal generator or the sensing unit than thesecond area is from the driving signal generator or the sensing unit,and wherein a first frequency of the first driving signal provided tothe first area among the driving signals is smaller than a secondfrequency of the second driving signal provided to the second area amongthe driving signals.
 4. The input sensing device of claim 1, wherein thedriving signal generator sequentially provides the driving signals tothe electrodes.
 5. The input sensing device of claim 1, wherein thedriving signal generator simultaneously provides the driving signals tothe electrodes.
 6. The input sensing device of claim 1, wherein thedriving signal generator includes: a waveform generator which generatesa reference signal, and a frequency modulator which varies a frequencyof the reference signal through frequency division and generates thedriving signals.
 7. The input sensing device of claim 1, wherein thesensing unit samples the first sensing signal N times during a referencetime, and samples the second sensing signal N times during the referencetime, and wherein N is an integer greater than four.
 8. The inputsensing device of claim 1, wherein a first sensing value generated bysampling the first sensing signal during a reference time duration isdifferent from a second sensing value generated by sampling the secondsensing signal during the reference time duration, and whereinattenuation of the first driving signal and the first sensing signal iscompensated by a difference between the first sensing value and thesecond sensing value.
 9. The input sensing device of claim 7, whereinthe reference time duration is smaller than or equal to a first periodof the first driving signal.
 10. The input sensing device of claim 9,wherein the reference time duration is smaller than half of the firstperiod of the first driving signal, and wherein each of the sensingsignals according to the first driving signal has a maximum value duringthe reference time duration.
 11. The input sensing device of claim 7,wherein amplitudes of the driving signals are different from each other.12. The input sensing device of claim 11, wherein an amplitude of atleast one of the driving signals is variable, and wherein each of thedriving signals has a maximum amplitude during the reference timeduration.
 13. The input sensing device of claim 1, wherein the sensingunit includes: analog front-ends which receive sensing signals accordingto the driving signals from the electrodes; and a signal processing unitwhich determines whether a touch is performed based on differentialoutput values of the analog front-ends.
 14. The input sensing device ofclaim 13, wherein each of the analog front-ends includes: a chargeamplifier which differentially amplifies a first sensing signal and asecond sensing signal respectively provided from two electrodes adjacentto each other among the electrodes and outputs a first differentialsignal and a second differential signal complementary to each other; aband pass filter which filters the first differential signal and thesecond differential signal and outputs a first filtered signal and asecond filtered signal, respectively; a mixer which changes frequenciesof the first filtered signal and the second filtered signal and outputsa first demodulated signal and a second demodulated signal,respectively; a low pass filter which filters noise from the firstdemodulated signal and the second demodulated signal and outputs a firstoutput signal and a second output signal, respectively; and ananalog-to-digital converter which outputs a differential output valuecorresponding to a difference between the first output signal and thesecond output signal.
 15. The input sensing device of claim 14, furthercomprising: a distribution circuit which is disposed between at leastsome of the electrodes and the analog front-ends, and provides each ofthe sensing signals provided from at least some of the electrodes to twoadjacent analog front-ends of the analog front-ends.
 16. The inputsensing device of claim 13, further comprising: a negative capacitorconnected to each of the analog front-ends.
 17. The input sensing deviceof claim 13, wherein each of the analog front-ends includes: amultiplexer which selects two sensing signals from sensing signalsprovided from three adjacent electrodes among the electrodes; a chargeamplifier which differentially amplifies the two sensing signalsselected from the sensing signals and outputs a first differentialsignal and a second differential signal complementary to each other; aband pass filter which filters the first differential signal and thesecond differential signal and outputs a first filtered signal and asecond filtered signal, respectively; a mixer which changes frequenciesof the first filtered signal and the second filtered signal and outputsa first demodulated signal and a second demodulated signal,respectively; a low pass filter which filters noise from the firstdemodulated signal and the second demodulated signal and outputs a firstoutput signal and a second output signal, respectively; and ananalog-to-digital converter which outputs a differential output valuecorresponding to a difference between the first output signal and thesecond output signal.
 18. The input sensing device of claim 17, whereinthe multiplexer selects a first sensing signal and a second sensingsignal from the sensing signals in a first section, and selects a secondsensing signal and a third sensing signal from the sensing signals in asecond section different from the first section, and wherein the firstto third sensing signals are respectively provided from the threeadjacent electrodes.
 19. A display device comprising: a display panelincluding pixels which emit light in unit of a frame; an input sensingpanel which includes electrodes; a driving signal generator whichprovides driving signals to the electrodes, respectively; and a sensingunit which receives sensing signals according to the driving signalsfrom the electrodes, wherein the driving signals include a first drivingsignal and a second driving signal which have different frequencies, andwherein the sensing unit samples a first sensing signal according to thefirst driving signal and a second sensing signal according to the seconddriving signal at a same frequency.
 20. The display device of claim 19,wherein the driving signal generator provides the driving signals to theelectrodes by avoiding a section in which a pulse of a verticalsynchronization signal defining a start of the frame is generated. 21.The display device of claim 20, wherein the driving signal generatorblocks a supply of the driving signals in the section in which the pulseof the vertical synchronization signal is generated.
 22. The displaydevice of claim 20, wherein the driving signals are asynchronous with ahorizontal synchronization signal, and wherein the horizontalsynchronization signal defines a section in which a line image is outputthrough pixels included in a same line among the pixels.